Microscope system

ABSTRACT

A microscope system includes a microscope body, a camera connected to an observation optical system of the microscope body, and an XY stage on which a slide of an observation object is placed and which is configured to move in an X-axis direction and a Y-axis direction that are orthogonal to each other. The XY stage includes an XY two-dimensional scale plate. The XY two-dimensional scale plate includes a first mark configured to provide X-axis direction axis information and Y-axis direction axis information of the stage, and a second mark which is provided within an observable region of the camera on the same plane as the first mark and which is available for recognizing a position of an XY plane of the first mark in a Z-axis direction at each of a plurality of points by focus detection of the camera.

TECHNICAL FIELD

The present invention relates to a microscope system.

BACKGROUND ART

The incidence rate of cancer has recently shown a tendency to greatlyincrease. To treat cancer, pathological diagnosis for diagnosingproperties of cancer is important, and a treatment policy is determineddepending on the diagnosis contents. As for the growth mechanism ofcancer, it has been understood that cancer is caused by genes. Atumultus that has occurred in a gene appears as an atypicalintracellular morphology, atypical cell morphology, atypical tissuemorphology, or the like. It is morphological diagnosis in pathologicaldiagnosis that observes these atypical shapes by a microscope anddetermines the atypism caused by cancer (tissue type).

On the other hand, recent medical advances have revealed thatoverexpression of a specific protein coded by an oncogene is oftenobserved in a cancer cell. Characteristics of cancer can be specified bydetecting the excessive protein. The protein is detected by, forexample, specifically staining the target protein and observing thedegree of staining of a tissue on a cell basis using a microscope. Thismethod determines a functional feature of cancer and is calledfunctional diagnosis in pathological diagnosis.

In both of the above-described morphological diagnosis and functionaldiagnosis, it is essential to observe the micro-level fine structure ofa tissue slice in detail using a microscope (to be referred to as microobservation or micro diagnosis hereinafter). An optical microscope is aparticularly important tool for a pathologist. In micro diagnosis by thenaked eye using a microscope, it is often necessary to record findingimages that are important as evidence. Hence, a digital camera ismounted on the optical microscope and used to record finding images. Adigital scanner or digital microscope incorporating a digital camera(image sensor) is also usable. In addition to the microscope, thedigital camera that provides an imaging function is also being includedin the tools important for the pathologist. For example, a digitalmicroscope incorporating a digital camera (image sensor) (JapanesePatent No. 4600395) can easily capture an evidence image as neededduring the process of diagnosis. Hence, the digital microscope is veryconvenient and is desired to be used not only for cancer but widely inpathological diagnosis.

Generally, in pathological diagnosis by a pathologist, morphologicaldiagnosis of a tissue slice is conducted in accordance with a procedureto be described below. In screening performed first in morphologicaldiagnosis, a slide glass (to be referred to as a slide hereinafter) onwhich a tissue slice that has undergone general staining (HE staining)is placed is observed by a microscope at a low magnification(low-magnification observation), thereby specifying a morbid portioncalled a region of interest (ROI). The specified ROI is observed at ahigh magnification (high-magnification observation), thereby makingdetailed diagnosis.

When the wavelength is, for example, 550 nm, the focal depths of a 4×objective lens and a 10× objective lens used in low-magnificationobservation are about 21 μm and about 3.5 μm, respectively. These focaldepths are much larger than or almost equal to the thickness (3 to 5 μm)of a tissue slice of an observation object. For this reason, thepathologist can conduct the screening only by moving the XY stage(slide) of the microscope. On the other hand, in high-magnificationobservation, a 20× objective lens, a 40× objective lens, or a 100×objective lens is used. In this case, when the wavelength is, forexample, 550 nm, the focal depths are about 1 μm in the 20× objectivelens, about 0.6 μm in the 40× objective lens, and about 0.3 μm in the100× objective lens. In the high-magnification observation, the focaldepths are considerably smaller than the thickness (3 to 6 μm) of thetissue slice of the observation object. Hence, in the high-magnificationobservation of diagnosis after the screening, the tissue slice of theobservation object needs to be moved in the Z direction. The pathologistobserves the tissue slice while moving the Z stage in addition to the XYstage.

The movement of the Z stage in the high-magnification observation isnecessary not only for the above-described detailed observation of thetissue slice in the thickness direction but also from the viewpoint tobe described below. That is, the perpendicularity of the observationsurface of the XY stage of the microscope with respect to the opticalaxis is determined by the mechanical accuracy of the microscope.Normally, there can exist a tilt of about 50 μm at worst in the slidemovable range (for example, 76 mm). Even in the range of a tissue slicesize (for example, 27 mm), a tilt of about 20 μm can exist at worst.Note that in this specification, “tilt” indicates a moderate waving ormoderate slant of a surface (the flatness or parallism is not 0). Aslide glass on which a tissue slice is placed also has a tilt of, forexample, about 20 μm at worst. For this reason, when the XY stage ismoved, the Z position of the tissue slice moves in accordance with thetilt amount of the XY stage or the slide, and the tissue slice shiftsfrom the focus position. Hence, the operation of the Z stage isimportant. The pathologist repetitively conducts observation using a lowmagnification and a high magnification while moving the observationfield, that is, while moving the XY and Z stages (slide) of themicroscope.

In addition, the pathologist screens the specimen placed on the slide asa whole at a low magnification, and memorizes/records the position ofthe stage at which the part (ROI) that needs detailed observation hasbeen observed. After ending the screening at the low magnification, thepathologist searches for the observation position of the ROI based onthe memorized/recorded XY stage position, switches the magnification tothe high magnification, and makes a diagnosis while moving the XY stageand the Z stage. Alternatively, the pathologist may use a procedure ofimmediately observing, at the high magnification, the ROI found by thelow-magnification screening.

On the other hand, in functional diagnosis, normally, functionalstaining (for example, functional staining by immunohistochemicalstaining in contrast to morphological staining in morphologicaldiagnosis) is performed for continuous tissue slices having a specificfinding in morphological diagnosis, and the tissue slices are observedby the microscope. That is, morphological information and functionaldiagnosis information are compared and observed between slides. For thisreason, in functional diagnosis, it is useful in terms of diagnosis toaccurately align a morphological image by general staining (HE staining)and (a plurality of) functional images by functional staining,superimpose the images, and compare and observe a morphological atypismand a function change. In morphological diagnosis as well, it is usefulin terms of diagnosis to accurately align the morphological images of aplurality of slides created from a plurality of adjacent slices, displaythe morphological images that are superimposed, and observe athickness-direction change in the tissue.

In the microscope system, however, it is impossible to reproduce anobservation position or a three-dimensional (XYZ) position of stillimage capturing at an accuracy capable of standing up to pathologicaldiagnosis. For example, in the above-described morphological diagnosis,after the diagnosis at the high magnification ends, the observationposition needs to be returned to the position in the low-magnificationscreening immediately before. Hence, the position (XY position) of theXY stage immediately before needs to be memorized. That is, thepathologist specifies the observation position of the ROI based on thememory of the manual operation amount in operating the XY stage and thememory of a corresponding observation image. Additionally, to observethe ROI at the high magnification again for reconfirmation from thescreening portion at the low magnification, the operation of the Z stage(Z position) is necessary in addition to the operation of the XY stage(XY position). In this case as well, it is necessary to rely on thememory of the manual operation amount and the memory of thecorresponding observation image. In particular, the Z stage needs to beoperated at various XY positions because of the tilt that exists on theXY stage and the slide surface. Since the Z stage operation count isexcessive, the burden on the pathologist is heavy. Note that if the tiltdoes not exist, the tissue slice can be moved in the same Z plane bymoving the XY stage, and the operation of the Z stage along with themovement of the XY stage is unnecessary.

This is because the general microscope system includes no means forgrasping the coordinates of an observation position easily at anecessary accuracy. For example, if the accompanying XY stage is amanual stage, the coordinate obtaining means is formed from, forexample, a main scale and a subscale, like a vernier caliper. However,it is not easy to read coordinate values from the positionalrelationship between the main scale and the subscale. In addition, theminimum reading accuracy is about 1/10 mm, which is too coarse in microobservation. In addition, if the accompanying Z stage is a manual stage,the coordinate obtaining means is formed from, for example, scalesnotched in a coarse moving knob and a fine moving knob. However, it isnot easy to read coordinate values from the positional relationshipbetween the coarse moving knob and the fine moving knob. In addition,the minimum reading accuracy is about 1/10 mm, which is too coarse inmicro observation, like the XY position.

A motor-driven XY stage includes, for example, an X stage that moves inthe X direction, and a Y stage that is provided on the X stage and movesin the Y direction. Each of the X stage and the Y stage includes alinear encoder configured to measure a moving amount in a correspondingdirection. In this case, a position in the X direction is obtained fromthe linear encoder of the X stage, and a position in the Y direction isobtained from the linear encoder of the Y stage. Then, the X- andY-coordinate values of the Y stage on which a slide is placed areobtained based on both pieces of position information. With the indirectmeasurement method of separately obtaining the X- and Y-directionpositions, it is difficult to obtain position information of an accuracyrequired for pathological diagnosis because of coordinate errors causedby, for example, mechanical errors of the X and Y stages.

In a motor-driven Z stage, for example, a linear encoder is incorporatedin the microscope base stand of the microscope to which the Z stage isattached. Hence, obtained position information in the Z direction isonly usable to grasp the Z-direction moving amount of the Z stageitself, and does not represent the Z position of a certain observationposition. In addition, the Z stage moving mechanism itself aims atvertically moving the XY and Z stages which may weigh, for example,about 5 kg in total within the movable range of about 5 cm, and isbarely able to ensure a reproducibility of 10 to 100 μm as a movingaccuracy. Hence, for example, the minimum size of a region of interest(ROI) in pathological diagnosis is about 1 μm, and the positionmanagement accuracy necessary to reproduce the observation position isneeded to be about 1 μm, probably. However, there exists no microscopesystem including XY and Z stages that meet the position managementaccuracy.

In microscopic observation (high-magnification observation) using ahigh-magnification objective lens, the focal depth is smaller than thethickness of a tissue slice. For this reason, even in a case in whichthe accuracy of the stage in the XY and Z directions is ensured, if atilt exists on the XY plane in which the stage moves (the normaldirection of the XY plane does not align with the optical axis directionof the microscope), the position in the Z direction changes as the stageis moved in the X or Y direction. Hence, if the tilt of the XY planechanges on a microscope basis, the position in the Z direction cannotcorrectly be reproduced, and a different image (an image at a differentZ direction) is observed even if the positions in the XY and Zdirections can correctly be controlled.

Hence, the general microscope system conventionally does not include ameans for correcting the tilt of the XY stage and the tilt of a slide asan assumption for reproduction of a position in the Z direction and ameans for grasping the coordinates of an observation position in the Zdirection easily at a necessary accuracy.

SUMMARY OF INVENTION

An embodiment of the present invention has been made in consideration ofthe above-described problems, and provides a microscope system capableof managing the position of a stage surface in the optical axisdirection at an accuracy required for pathological diagnosis.

According to one aspect of the present invention, there is provided amicroscope system comprising: a microscope body; a camera connected toan observation optical system of the microscope body; and an XY stage onwhich a slide of an observation object is placed and which is configuredto move in an X-axis direction and a Y-axis direction that areorthogonal to each other, wherein the XY stage comprises an XYtwo-dimensional scale plate, and the XY two-dimensional scale platecomprises: a first mark configured to provide X-axis direction axisinformation and Y-axis direction axis information of the XY stage; and asecond mark which is provided within an observable region of the cameraon the same plane as the first mark and which is available forrecognizing a position of an XY plane of the first mark in a Z-axisdirection at each of a plurality of points by focus detection of thecamera.

Further features of the present invention will become apparent from thefollowing description of exemplary embodiments with reference to theattached drawings.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a perspective view showing a microscope system according to anembodiment.

FIG. 2 shows views illustrating the outline of the arrangement of theoptical system of the microscope system according to the embodiment.

FIG. 3 shows a view illustrating the outer appearance of the microscopesystem (3 a), a view for explaining the mounted state of a ΔZ stage (3b), and a view for explaining a Z scale and a Z sensor (3 c).

FIG. 4 is a view for explaining mounting of the ΔZ stage on a Z base andplacement of a stage.

FIG. 5 shows views for explaining the structure of the lift unit of theΔZ stage (5 a to 5 e).

FIG. 6 shows views for explaining mounting of the ΔZ stage on the stage(6 a to 6 c).

FIG. 7 shows a view illustrating the outer appearance of the stagemounted in a microscope according to the embodiment (7 a), a viewillustrating the upper surface of the stage (7 b), and an enlarged viewof a portion of an area scale (7 c).

FIG. 8 shows a side view illustrating a position management plane stage(X stage) (8 a) and views for explaining the positional relationshipbetween an XY two-dimensional scale plate and X- and Y-axis sensors (8 band 8 c).

FIG. 9 shows views illustrating the positional relationship between Xand Y area scales, X- and Y-axis sensors, and skew detecting sensors (9a and 9 b).

FIG. 10 shows views illustrating the positional relationship between theX and Y area scales, the X- and Y-axis sensors, and the skew detectingsensors (10 a and 10 b).

FIG. 11 shows views for explaining an XY crosshatch provided on the XYtwo-dimensional scale plate (11 a and 11 b).

FIG. 12 shows views for explaining the XY crosshatch provided on the XYtwo-dimensional scale plate (12 a to 12 c).

FIG. 13 shows views illustrating the mounted state of a ΔΘ stage on theposition management plane stage (13 a and 13 b).

FIG. 14 shows views for explaining the arrangement of the ΔΘ stage (14 ato 14 c).

FIG. 15 shows views illustrating the structure of the lift unit of theΔΘ stage (15 a to 15 e).

FIG. 16 shows views for explaining mounting of the ΔΘ stage on theposition management plane stage (16 a to 16 c).

FIG. 17 shows views for explaining rotation correction by the ΔΘ stage(17 a and 17 b) and a view for explaining rotation of a slide placed onthe ΔΘ stage (17 c).

FIG. 18 shows views illustrating the position management plane stage (18a and 18 b).

FIG. 19 shows views illustrating a Y stage (19 a and 19 b).

FIG. 20 is a view showing a stage base.

FIG. 21 is a view for explaining an adapter unit used to mount a camera.

FIG. 22 shows views for explaining a ΔC adapter (22 a and 22 b).

FIG. 23 shows a view illustrating a slide glass (23 a) and views showingthe reference marks of the slide glass (23 b and 23 c).

FIG. 24 shows a view illustrating another example of the slide glass (24a) and a view for explaining focus reference marks (24 b).

FIG. 25 is a block diagram showing an example of the control arrangementof the microscope system according to the embodiment.

FIG. 26 is a block diagram showing an example of the control arrangementof the microscope system according to the embodiment.

FIG. 27 is a flowchart showing the overall operation of the microscopesystem according to the embodiment.

FIG. 28 is a flowchart showing the initialization operation of eachportion of the microscope system.

FIG. 29 is a flowchart showing tilt correction processing for the XYstage.

FIG. 30 is a flowchart for explaining a correction operation by the ΔCadapter.

FIG. 31 shows views for explaining rotation correction between an imagesensor and a stage (31 a to 31 e).

FIG. 32 is a flowchart showing a stage origin detection operation.

FIG. 33 shows views for explaining the stage origin detection operation(33 a and 33 b).

FIG. 34 is a flowchart showing tilt correction processing for a slide.

FIG. 35 is a flowchart for explaining a correction operation by the ΔΘstage.

FIG. 36 shows views for explaining rotation correction between the imagesensor and the slide (36 a to 36 c).

FIG. 37 is a flowchart showing an operation of detecting the origin ofthe slide.

FIG. 38 shows views for explaining the slide origin detection operation(38 a to 38 e).

FIG. 39 is a flowchart for explaining processing of measuring the δZdistribution on a slide surface.

FIG. 40 is a flowchart for explaining generation and recording of animage file.

FIG. 41 is a view showing an example of the data structure of an imagefile.

FIG. 42 is a flowchart showing processing of synchronizing a display andan observation position on a stage.

FIG. 43 is a view for explaining synchronization between a display andan observation position on a stage.

FIG. 44 shows views for explaining the influence of a rotational shiftbetween the X- and Y-axes of a captured image and the X- and Y-axes ofthe stage (44 a and 44 b).

FIG. 45 shows views for explaining skew processing according to theembodiment (45 a and 45 b).

FIG. 46 shows views for explaining skew processing according to theembodiment (46 a and 46 b).

FIG. 47 shows views for explaining skew processing according to theembodiment (47 a and 47 b).

FIG. 48 is a flowchart for explaining processing upon switching anobjective lens.

FIG. 49 shows a view illustrating a cover glass with focus referencemarks (49 a), a view for explaining a method of obtaining the thicknessof a tissue slice using the cover glass with focus reference marks (49b), and a view for explaining the relationship between the cover glassand a focus position (49 c).

FIG. 50 shows views for explaining calculation of the δZ distribution(50 a and 50 b).

FIG. 51 shows views for explaining calculation of the δZ distribution(51 a and 51 b).

FIG. 52 shows views for explaining the focus reference marks used tocorrect the tilt of the ΔZ stage (52 a to 52 c).

DESCRIPTION OF EMBODIMENTS

An embodiment of the present invention will now be described withreference to the accompanying drawings. Note that an erect-typemicroscope used for pathological diagnosis, which includes an objectivelens arranged above an observation object (slide) and performstransmitted light observation by projecting observation light from thelower surface of the slide, will be described below as an embodiment ofthe present invention.

An observation position management microscope system according to thisembodiment can manage an observation position at a predeterminedaccuracy required for pathological diagnosis and correctly reproduce apast observation position. For this purpose, the observation positionmanagement microscope system uses a slide with references for positionmanagement, and also includes an accurate XY stage with a means for,when a slide is placed, correcting a rotational error of the placedslide. In addition, the XY stage has a function of directly grasping theX- and Y-coordinate values of an observation position, and includes ameans for correcting, for example, an error of the relative positionalrelationship to a mounted digital camera (image sensor) or the like. Inaddition, the observation position management microscope systemaccording to this embodiment corrects the tilt of the XY stage or theslide to the digital camera, and implements management at apredetermined accuracy required for pathological diagnosis even for anobservation position in the height direction (the Z direction or theoptical axis direction of the digital camera).

The predetermined accuracy required for pathological diagnosis may bethe minimum size of a region of interest (ROI). Structures in a cell aredistributed within a range on the micron or submicron order. An atypismobserved here can be assumed to be an ROI in a minimum size obtained bypathological diagnosis. On the other hand, with a normally usedobjective lens for visible light, the resolution at a magnification of100× is about 0.2 μm (green light: 550 nm). When an objective lens forultraviolet light is used, the resolution can be raised to about 0.1 μm(ultraviolet light: 200 nm). Hence, the minimum size of an observableROI in the X and Y directions is, for example, 10 times larger than theultraviolet resolution limit of 0.1 μm, that is, 1 μm square. Hence, thetarget position management accuracy in the X and Y directions is 0.1 μmequal to the resolution limit. Coordinate management is done at, forexample, 1/10 of the accuracy, that is, in steps of 0.01 μm.

On the other hand, a 100× objective lens that can be considered to havethe maximum magnification of an objective lens has a focal depth ofabout 0.3 μm for green light (550 nm). An objective lens for ultravioletlight has a focal depth of about 0.1 μm (ultraviolet light: 200 nm).That is, the minimum size of the ROI in the Z direction is, for example,10 times larger than the focal depth (0.1 μm) of the objective lens forultraviolet light resolution limit of 0.1 μm, that is, 1 μm. Hence, thetarget position management accuracy in the Z direction is 0.1 μm equalto the minimum focal depth. Coordinate management is done at, forexample, 1/10 of the accuracy, that is, in steps of 0.01 μm. Hence, theminimum size of the ROI is the cube of 1 μm, the position managementaccuracy is the cube of 0.1 μm, and the coordinate management unit is,for example, 1/10 of the position management accuracy, that is, the cubeof 0.01 μm.

An observation position management microscope system that implements theposition accuracy in a three-dimensional space including X and Ydirections defining the moving plane of an XY stage that moves with aslide as an observation object of the microscope placed on it and a Zdirection perpendicular to the moving plane will be described below. Theobservation position management microscope system according to thisembodiment includes a predetermined support means for supporting even anexisting slide without a reference for position management from theviewpoint of compatibility.

FIG. 1 is a perspective view showing the basic arrangement of anobservation position management microscope system (to be referred to asa microscope system 10 hereinafter) according to this embodiment. Themicroscope system 10 includes a microscope body 100, a stage 200, anadapter unit 300 used to mount a camera, a digital camera 400, a controlunit 500, and a ΔZ stage 900. The stage 200, the adapter unit 300, thedigital camera 400, and the ΔZ stage 900 have arrangements and functionssupporting position management according to this embodiment. The controlunit 500 includes a controller 501 and a display 502. The controller 501includes a CPU 511 and a memory 512 (see FIG. 25). The CPU 511 executesa program stored in the memory 512, thereby executing various kinds ofprocessing to be described later. The controller 501 controls display onthe display 502 serving as a display unit.

A microscope base stand 121 that constitutes the microscope body 100 isa solid body frame used to attach various structures of the microscope.An eyepiece base 122 is fixed to the microscope base stand 121 andconnects an eyepiece barrel 123 (in this example, binocular). A lightsource box 124 stores a light source (for example, a halogen lamp orLED) for transmission observation and is attached to the microscope basestand 121. A Z knob 125 is a knob used to move a Z base 130 in theZ-axis direction (vertical direction). The ΔZ stage 900 that provides aposition management function in the Z direction is mounted on the Z base130, and the stage 200 that provides a position management function inthe X and Y directions is placed on the ΔZ stage 900. The Z base 130 ismounted on the microscope base stand 121 by a Z-base moving mechanism131 (see (2 a) of FIG. 2) that moves the Z base 130 in the Z directionin accordance with the rotation of the Z knob 125. The ΔZ stage 900corrects the tilt of the stage 200 with respect to the optical axis ofthe digital camera 400 or the optical axis of the lens of the microscopebody, and implements accurate positioning of the observation position inthe Z direction. Reference numeral 126 denotes an objective lens unit.There exist a plurality of types of units according to opticalmagnifications. A revolver 127 has a structure capable of attaching theplurality of types of objective lens units 126. By rotating the revolver127, a desired objective lens unit can be selected for observation bythe microscope.

The stage 200 includes a ΔΘ stage 600 that rotates about the Z-axiswhile having a slide (to be referred to as a slide 700 hereinafter) withposition references placed on it, and an XY stage that moves the ΔΘstage 600 with the slide 700 placed on it on an XY plane including the Xdirection and the Y direction. The ΔΘ stage 600 provides a function ofcorrecting a rotational shift based on the position reference marks onthe slide 700, and also provides a function of correcting the tilt ofthe surface of the slide 700 with respect to the optical axis of thedigital camera 400 or the optical axis of the lens of the microscopebody (to be simply referred to as an optical axis hereinafter). Thestage 200 includes an XY two-dimensional scale plate 210 with accuratescales in the X and Y directions on the XY stage. An X knob 201 and a Yknob 202 are knobs used to manually move the stage 200 in the Xdirection and Y direction, respectively. A ΔZ knob 904 is a knob used tomanually move the ΔZ stage 900 in the Z direction.

The adapter unit 300 is an adapter used to mount a camera, whichfunctions as a mounting unit configured to mount the digital camera 400on the eyepiece base 122 via a base mount 128. The adapter unit 300 hasa function of performing axis alignment between the digital camera 400and the base mount 128. The base mount 128 includes a predeterminedmounting mechanism, for example, a screw mechanism with a positioningreference.

The digital camera 400 is detachably attached to the microscope body 100via the adapter unit 300 and the base mount 128 while maintaining apredetermined positional relationship to the eyepiece base 122. Thedigital camera 400 captures a microscope image obtained by themicroscope body 100. The digital camera 400 aims at evidence recording.The digital camera 400 is connected to the controller 501 via, forexample, a USB interface cable 11, and captures an observed image underthe microscope in accordance with an instruction from the controller501. The captured observed image is displayed on the display 502 underthe control of the controller 501. The imaging function of the digitalcamera 400 includes a still image capturing function and a live imagecapturing function of performing so-called live view that displays anoutput from an image sensor on a monitor in real time. The resolution ofthe live image capturing function is lower than that of the still imagecapturing function. The live image capturing function and the stillimage capturing function can transmit a captured image (a moving imageor a still image) to an external apparatus via a predetermined interface(in this embodiment, a USB interface).

FIG. 2 shows schematic views for explaining the optical system of themicroscope system 10 according to this embodiment. As shown in (2 a) ofFIG. 2, the light source box 124 stores a light source 141 fortransmission observation, and a collector lens 142 that collects sourcelight from the light source 141. A field stop 143 determines theillumination diameter on the slide. The source light that has passedthrough the field stop 143 passes through a mirror 144, a relay lens145, an aperture stop 146, and a condenser lens 147 and irradiates aspecimen (tissue slice) on the slide. The light transmitted through thespecimen on the slide glass enters an objective lens 148 in theobjective lens unit 126. The light that has passed through the objectivelens 148 reaches a split prism 150 via an imaging lens 149. Note thateach of the collector lens 142, the relay lens 145, the condenser lens147, the objective lens 148, and the imaging lens 149, and the like isnormally formed from a combination of a plurality of lenses.

The split prism 150 is also called a beam splitter, and has a functionof switching the optical path of an optical image from the objectivelens 148 to an eyepiece optical system or an imaging optical system. Forexample, a reflecting prism for the eyepiece optical system and astraight prism for the imaging optical system are replaced by apush-pull rod. It is therefore possible to attain one of

-   -   a state in which only imaging by the digital camera 400 (image        sensor 401) is performed, and observation from the eyepiece        barrel 123 cannot be done, and    -   a state in which only observation from the eyepiece barrel 123        is performed, and imaging by the image sensor 401 cannot be        done.

In place of or in addition to the above-described arrangement, a halfmirror split prism that passes a half light amount to each of theeyepiece optical system and the imaging optical system may be arranged.In this case, a state in which both imaging by the image sensor 401 andobservation from the eyepiece barrel 123 can be performed can beprovided. When the split prism 150 is switched to the camera side, thelight transmitted through the tissue slice forms an image on the imagesensor 401 in the digital camera 400 via an adapter lens 301. Thedigital camera 400 including the image sensor 401 captures the imageunder the microscope.

The optical path of the eyepiece system is an optical path to theeyepiece barrel 123. In FIG. 2, (2 b) is a view for explaining anexample of the eyepiece optical system of the eyepiece barrel 123, whichillustrates an example of a siedentopf binocular barrel. In (2 b) ofFIG. 2, the optical system on the right side is a left-eye opticalsystem. A left-eye split prism 151 forms an image on an imaging plane152 of the primary image of the left-eye system, and the image isobserved by the user via a left-eye eyepiece 153. On the other hand, theoptical system on the left side of (2 b) in FIG. 2 is a right-eyeoptical system. A right-eye parallel prism 154 forms an image on animaging plane 155 of the primary image of the right-eye system, and theimage is observed by the user via a right-eye eyepiece 156.

Referring back to (2 a) of FIG. 2, when the adapter unit 300 and thedigital camera 400 are mounted, the adapter lens 301 and the imagesensor 401 are arranged in the optical path of the imaging opticalsystem. The adapter lens 301 is a lens incorporated in the adapter unit300 attached to the eyepiece base 122, and is normally formed from aplurality of lenses. With the adapter lens 301, an observation image isformed on the imaging plane of the image sensor 401 disposed in thedigital camera 400, and the microscope image can be captured by thedigital camera 400.

The ΔZ stage 900 will be described next. In FIG. 3, (3 a) is aperspective view of the microscope body 100 viewed from a directiondifferent from that in FIG. 1. In FIG. 3, (3 b) is a view showing themounted state of the ΔZ stage 900 on the Z base 130. The microscope basestand 121 is provided with a Z scale 990 used to measure the Z-directionposition of the Z base 130. The Z scale 990 is used to measure a movingamount by a Z sensor 991 mounted on a ΔZ base 901. The stage 200 ismounted on the Z base 130 of the microscope body 100 via the ΔZ stage900. The ΔZ stage 900 is mounted on the Z base 130. As shown in (3 c) ofFIG. 3, the Z scale 990 includes a Z initial position mark 990 a and a Zlinear scale 990 b. The Z sensor 991 includes a Z initial positionsensor 991 a and a Z-axis sensor 991 b. The Z initial position sensor991 a detects the Z initial position mark 990 a, and the Z-axis sensor991 b reads the Z linear scale 990 b. Note that the Z linear scale 990 bhas the same pattern as that of an X area scale 211 ((7 c) of FIG. 7,and the like) to be described later, and is formed as a linear scalewith a narrower scale width. Like the X area scale 211, the Z linearscale 990 b includes, for example, transmission parts andlight-shielding parts, each of which is a line having a width of 2 μm.The transmission parts and the light-shielding parts are disposed inpairs at a pitch of 4 μm. Using the Z linear scale 990 b and the Z-axissensor 991 b, a resolution of 10 nm (0.01 μm) or less and a positionaccuracy of 0.1 μm are implemented by, for example, a 1/2000interpolation operation. Note that in this embodiment, incremental typeposition measurement is executed by the Z linear scale 990 b and theZ-axis sensor 991 b. However, absolute type position measurement may beperformed. In the absolute type, the Z initial position mark 990 a andthe Z initial position sensor 991 a can be omitted.

FIG. 4 is a view for explaining mounting of the ΔZ stage 900 on the Zbase 130 and mounting of the stage 200 on the ΔZ stage 900. The Z base130 and the ΔZ stage 900 are fixed by Z base attachment holes 902provided in the ΔZ base 901 and screws 992. At this time, positioningpins 993 provided on the Z base 130 are fitted in positioning holes 903of the ΔZ base 901, thereby improving the accuracy of the ΔZ stage 900with respect to the Z base 130 in mounting. ΔZ lift units 910 configuredto adjust the tilt of the stage 200 are mounted at a plurality ofpoints, in this example, three points on the ΔZ base 901 of the ΔZ stage900. A stage base 260 in the lowermost portion of the stage 200 isprovided with spring hooks 995 configured to catch stage holding springs917 of the ΔZ lift units 910. When the stage holding springs 917 of thethree ΔZ lift units 910 are caught on the spring hooks 995 provided onthe stage base 260, the stage 200 is pressed against the ΔZ stage 900.Spherical bearings 996 are press-fitted in the lower surface of thestage base 260 of the stage 200. In a state in which the stage 200 ispressed against the ΔZ stage 900 by the stage holding springs 917, liftpins 914 of the ΔZ lift units 910 are fitted in the spherical bearings996 of the stage base 260. At this time, sensor plates 919 are insertedinto sensor plate holes 997. Note that the stage 200 can also be fixedto the Z base 130 directly (without intervention of the ΔZ stage 900)using Z base attachment holes 902 a and positioning holes 903 a of thestage base 260. This aims at introducing an add-on ΔZ stage forproviding a more advanced function. When a ΔZ motor 913 of a ΔZ liftunit 910 is driven, the lift pin 914 moves in the vertical direction.The slant of the XY plane of the stage 200 is controlled by verticallymoving the lift pins 914 of the plurality of ΔZ lift units 910.

FIG. 5 shows views for explaining the structure of the lift unit 910. InFIG. 5, (5 a) to (5 c) are perspective views of the ΔZ lift unit 910,and (5 d) is a sectional view of the ΔZ lift unit 910. A holder 911 is asupport mechanism that plays the role of a housing to dispose eachmechanism of the ΔZ lift unit 910. In this embodiment, the three ΔZ liftunits 910 are arranged as shown in (5 e) of FIG. 5. Of the lift pins 914(ΔZ lift pins L1 to L3) of the three ΔZ lift units 910, two ΔZ lift pins(L1 and L2) are arranged on the microscope base stand side at aninterval Rh in the X direction, and the remaining one ΔZ lift pin (L3)is arranged on the far end side with respect to the microscope basestand so as to form, for example, an isosceles triangle having a heightRi. A linear guiderail 915 is fixed to the holder 911. A slide block 916is attached slidably with respect to the linear guiderail 915. A liftblock 912 is fixed to the slide block 916 to be movable along the linearguiderail 915 together with the slide block 916. The lift block 912 isprovided with the lift pin 914 that comes into contact with thespherical bearing 996 of the stage base 260.

The ΔZ motor 913 is fixed to the holder 911. A ball screw 918 isprovided on the rotating shaft of the ΔZ motor 913. As the ΔZ motor 913,for example, an ultrasonic motor can be used. However, the presentinvention is not limited to this. A multilayered piezoelectric elementmay be used in place of the ΔZ motor 913. The lift block 912 includes anut 918 a that moves as the ball screw 918 rotates. With this structure,the lift block 912 can be moved along the linear guiderail 915 byrotating the ΔZ motor 913. The ΔZ motor 913, the ball screw 918, the nut918 a, the linear guiderail 915, and the slide block 916 constitute thelinear driving mechanism of the lift block 912, which converts therotation of the ΔZ motor 913 into the vertical movement of the liftblock 912. The Z-direction position of the lift pin 914 can thus bemoved to an arbitrary position. The stage holding spring 917 that is anelastic member has one end caught on a hold pin 921 provided on theholder 911 and the other end caught on the spring hook 995 provided onthe stage base 260. The spherical bearing 996 is thus pressed againstthe lift pin 914, and the stage base 260 can be stabilized on the ΔZbase 901. In addition, the Z-direction position and the surface slant ofthe stage 200 can finely be adjusted by moving the lift pin 914 up anddown. The sensor plate 919 on which a ΔZ sensor 920 configured to read aΔZ scale 994 ((6 b) and (6 c) of FIG. 6) provided in the sensor platehole 997 of the stage base 260 is mounted is fixed to the holder 911.

In FIG. 6, (6 a) is a sectional view in a state which the ΔZ stage 900is fixed to the stage base 260 by the stage holding springs 917. Notethat (6 a) of FIG. 6 shows the stage base 260 and a Y stage 240 of thestage 200, and a position management plane stage (X stage) is notillustrated. In FIG. 6, (6 b) is a view showing details of the portionof the ΔZ lift unit 910 in the state in which the ΔZ stage 900 is fixedto the stage base 260. As described above, the ends of the stage holdingspring 917 are connected to the spring hook 995 and the hold pin 921.The lift pin 914 is thus brought into contact with the spherical bearing996, and the stage 200 is mounted on the ΔZ stage 900 to be movable inthe Z direction. The sensor plate 919 is inserted into the sensor platehole 997, and the ΔZ sensor 920 reads the ΔZ scale 994 provided on awall surface of the sensor plate hole 997 of the stage base 260.

In FIG. 6, (6 c) is a view showing an example of the ΔZ scale 994. TheΔZ scale 994 includes a ΔZ initial position mark 994 a and a ΔZ linearscale 994 b. Note that the Z-direction movable range of the stage base260 by the lift block 912 is about ±2 mm with respect to the ΔZ initialposition mark 994 a as the center. However, the present invention is notlimited to this, and ensuring a movable range necessary for adjustmentof the tilt of the stage 200 suffices. The ΔZ sensor 920 includes a ΔZinitial position sensor 920 a and a ΔZ-axis sensor 920 b. The ΔZ initialposition sensor 920 a detects the ΔZ initial position mark 994 a, andthe ΔZ-axis sensor 920 b reads the ΔZ linear scale 994 b. Note that theinitial position of the lift pin 914 of each ΔZ lift unit 910 isdetermined by the position of the ΔZ initial position mark 994 a. The ΔZlinear scale 994 b has the same pattern as that of the X area scale 211((7 c) of FIG. 7, and the like) to be described later, and is formed asa linear scale with a narrower scale width. Like the X area scale 211,the ΔZ linear scale 994 b includes, for example, transmission parts andlight-shielding parts, each of which is a line having a width of 2 μm.The transmission parts and the light-shielding parts are disposed inpairs at a pitch of 4 μm. Using the ΔZ linear scale 994 b and theΔZ-axis sensor 920 b, a resolution of 10 nm (0.01 μm) or less and aposition (management) accuracy of 0.1 μm are implemented by, forexample, a 1/2000 interpolation operation.

The arrangement of the stage 200 will be described next. In FIG. 7, (7a) is a perspective view showing the arrangement of the stage 200supporting position management. In (7 a) of FIG. 7, a positionmanagement plane stage 220 serving as an X stage is located on theuppermost surface of the stage 200 and moves in the X direction on the Ystage 240. The XY two-dimensional scale plate 210 and the ΔΘ stage 600are arranged and placed on the position management plane stage 220, andthe slide 700 is placed on the ΔΘ stage 600. The Y stage 240 moves inthe Y direction on the stage base 260. That is, in the stage 200, thestage base 260, the Y stage 240, and the position management plane stage220 constitute an XY stage. As described with reference to FIG. 4, thestage base 260 is mounted on the ΔZ stage 900 fixed to the Z base 130 ofthe microscope body 100 to be movable in the vertical direction by thelift pins 914.

In FIG. 7, (7 b) is a view showing the upper surface of the positionmanagement plane stage 220. As described above, the ΔΘ stage 600 and theXY two-dimensional scale plate 210 are disposed on the upper surface ofthe position management plane stage 220. An X area scale 211 havingX-direction axis information used for position management when moving inthe X direction, a Y area scale 212 having Y-direction axis informationused for position management when moving in the Y direction, and an XYcrosshatch 213 serving as an XY-axis alignment reference are formedhighly accurately on the upper surface of the XY two-dimensional scaleplate 210. Note that to form the references that implement accurateposition management, a material having a very small thermal expansioncoefficient, for example, synthetic quartz is used as the material ofthe XY two-dimensional scale plate 210, and the XY two-dimensional scaleplate 210 is integrally formed.

Nanotechnology of a semiconductor exposure apparatus or the like is usedto form the patterns of the X area scale 211, the Y area scale 212, andthe XY crosshatch 213 of the XY two-dimensional scale plate 210. Forexample, the X area scale 211, the Y area scale 212, and the XYcrosshatch 213 formed from sets of lines along the X- and Y-axes areintegrally formed on a quartz wafer by the nanotechnology at an accuracyof 5 nm to 10 nm. Note that the X area scale 211, the Y area scale 212,and the XY crosshatch 213 can be formed by drawing using a semiconductorexposure apparatus, but nanoimprint is preferably used to implement lowcost. After that, the wafer is cut into a predetermined shape bymachining, thereby obtaining the XY two-dimensional scale plate 210. Forthis reason, the degree of alignment between the X- and Y-axes of the Xarea scale 211 and the X- and Y-axes of the XY crosshatch 213, thedegree of alignment between the X- and Y-axes of the Y area scale 212and the X- and Y-axes of the XY crosshatch 213, and the perpendicularitybetween the X-axis and the Y-axis can be formed on the nanometer order.Hence, the X-axis and the Y-axis of the XY crosshatch 213 can representthe X-axes and the Y-axes of the X area scale 211 and the Y area scale212 at an accuracy of nanometer order. Note that the X area scale 211,the Y area scale 212, and the XY crosshatch 213 can also be individuallyseparated or separately formed and disposed on the position managementplane stage such that they hold a predetermined positional relationship.However, to implement this, an advanced alignment technique forcorrecting mechanical errors is needed, resulting in an increase in thecost.

The slide 700 is placed on the ΔΘ stage 600. As for the placementdirection, the slide 700 is placed such that, for example, a label area721 is located on the left side of an origin mark 701, and a cover glassarea 722 that is a region to arrange the observation object and a coverglass is located on the right side of the origin mark 701, as shown in(7 b) of FIG. 7. A region 205 indicated by a broken line is theobservation object region of the microscope. The observation objectregion 205 is a range in which the center position of the objective lens148 (or the center position (observation position) of the image sensor401) moves relative to the XY stage. The observation object region 205has a size to include the slide 700 and the XY crosshatch 213 with anallowance. This allows the slide 700 and the XY crosshatch 213 to bearranged in the observation object region 205 under any condition. Thatis, not only the slide 700 but also the XY crosshatch 213 are arrangedto be captured by the digital camera 400 serving as an imaging unit.

In this embodiment, a crosshatch origin on the XY crosshatch correspondsto the upper right corner of the observation object region 205. Inaddition, a state in which the center of the objective lens 148 (or thecenter (observation position) of the image sensor 401) aligns with thecrosshatch origin is defined as the XY coordinate origin of the stage200. However, another point may be defined as the XY coordinate originof the stage, as a matter of course. The XY coordinate origin of thestage and the initialization position of the stage mechanism are notalways the same. Note that the X-axis and the Y-axis of stagecoordinates, that is, a stage X-axis 203 and a stage Y-axis 204 areparallel to the X- and Y-axes of the XY crosshatch 213, respectively.

In FIG. 7, (7 c) shows an example of the scale pattern of the X areascale 211. The X area scale 211 is formed as a transmission diffractiongrating including transmission parts and light-shielding parts in the Xdirection to detect a position. For example, each of the transmissionparts and the light-shielding parts is a line having a width of 2 μm.The transmission parts and the light-shielding parts are disposed inpairs at a pitch of 4 μm. Note that the scale pattern may be a phasegrating that has step differences so as to periodically change theoptical path length.

In FIG. 8, (8 a) is a view showing the Z-direction positionalrelationship between the slide 700 and the X area scale 211, the Y areascale 212, and the XY crosshatch 213 on the XY two-dimensional scaleplate 210. As shown in (8 a) of FIG. 8, the position management planestage 220 and the ΔΘ stage 600 are designed such that the upper surfaceof the slide 700 and that of the XY two-dimensional scale plate 210become flush with each other at a predetermined accuracy. Hence, theupper surface of the ΔΘ stage 600 is lower than the upper surface of theXY two-dimensional scale plate 210 by an amount corresponding to thethickness of the slide 700. As described above, in this embodiment, theupper surface of the XY two-dimensional scale plate 210 (the surface onwhich the X area scale 211, the Y area scale 212, and the XY crosshatch213 are arranged) and the upper surface of the slide 700 are alignedwith each other (almost flush with each other). The Z-directionpositions of the marks (patterns) arranged on the XY two-dimensionalscale plate 210 can thus be aligned with those of the marks (patterns)provided on the slide 700. This makes it possible to accurately managethe XY position of the observation surface, that is, the upper surfaceportion of the slide 700 based on the external position references (theX area scale 211 and the Y area scale 212). Since the XY crosshatch 213represents the X area scale 211 or the Y area scale 212, it is importantthat the XY crosshatch 213 is located on the same plane as these areascales. Note that from the viewpoint of implementation, the uppersurface of the XY two-dimensional scale plate 210 (the surface on whichthe marks are arranged) and the upper surface of the slide 700 need onlyexist within the range of about 0.5 mm in the Z direction.

The scale pattern of the X area scale 211 or the Y area scale 212 isread by a detection sensor (an X-axis sensor 271 or a Y-axis sensor 272)fixed to the stage base 260, and the X- and Y-coordinates of the stage200 are directly accurately obtained in correspondence with anobservation position itself. That is, the microscope system does not usean indirect method in which a coordinate on one specific axis for eachaxis (X-axis or Y-axis) of the XY stage represents a coordinate value,for example, the coordinate values of the Y stage are obtained bycombining position information in the X direction obtained from thelinear encoder of the X stage and position information in the Ydirection obtained from the linear encoder of the Y stage. In thisembodiment, the movement of the position management plane stage (Xstage) 220 that moves in the X and Y directions is directly measured bythe XY two-dimensional scale plate 210. This allows the detection sensorto detect, for example, a small positional shift in the Y direction whenthe X stage 220 moves in the X direction or a small positional shift inthe X direction when the Y stage 240 moves in the Y direction accordingto a mechanical play or error. Hence, the accuracy of positionmanagement can largely be improved. There are two methods concerning theZ-direction positional relationship between the X area scale 211 and theY area scale 212 and the X-axis sensor 271 and the Y-axis sensor 272, asshown in (8 b) and (8 c) of FIG. 8. In (8 b) of FIG. 8 that shows thefirst method, the X-axis sensor 271 and the Y-axis sensor 272 arearranged above the XY two-dimensional scale plate 210 (on the objectivelens side). In this case, a light-shielding film 214 needs to beprovided on the lower surface of the XY two-dimensional scale plate 210.In (8 c) of FIG. 8 that shows the second method, the X-axis sensor 271and the Y-axis sensor 272 are arranged under the XY two-dimensionalscale plate 210 (on the side of the Z base 130). In this case, thelight-shielding film 214 is provided on the upper surface of the XYtwo-dimensional scale plate 210. Note that the XY crosshatch 213 needsto be observed by the digital camera 400, the light-shielding film isnot arranged at the position of the XY crosshatch 213.

In the first method, as shown in (8 b) of FIG. 8, the X-axis sensor 271and the Y-axis sensor 272 are implemented on the lower surface of asensor attachment member 208 that hangs over the position managementplane stage 220 via an L-shaped member 207 fixed to the stage base 260.The detection surfaces of the X-axis sensor 271 and the Y-axis sensor272 face downward to read the X area scale 211 and the Y area scale 212on the position management plane stage 220. In the second method, asshown in (8 c) of FIG. 8, the X-axis sensor 271 and the Y-axis sensor272, each having the detection surface facing upward, are implemented onthe stage base 260 such that the detection surfaces are located at apredetermined height. The X-axis sensor 271 and the Y-axis sensor 272 onthe stage base 260 located in the lowermost portion read, from the lowerside via holes each formed in the Y stage 240 and the positionmanagement plane stage 220 and having a predetermined size, the X areascale 211 and the Y area scale 212 located in the uppermost portion.

Note that the X- and Y-direction arrangements of the X-axis sensor 271and the Y-axis sensor 272 are common to the first and second methods.The attached position of the X-axis sensor 271 in the Y-direction is seton the X-axis passing through the field center (the center of theobjective lens 148) of an observation field 170 (illustrated much largerthan the size of the actual observation field) of the microscope,thereby ensuring the position detection accuracy in the X direction. Theattached position of the Y-axis sensor 272 in the X-direction is set onthe Y-axis passing through the center (the field center (the center ofthe objective lens 148)) of the observation field 170 (illustrated muchlarger than the size of the actual observation field) of the microscope,thereby ensuring the position detection accuracy in the Y direction. Bythe XY two-dimensional scale plate 210, the X area scale 211 and the Yarea scale 212 used to obtain the X-coordinate and the Y-coordinate ofthe stage 200, and the XY crosshatch for axis alignment (to be describedlater) of the image sensor 401 are provided on the same surface of thesame member. It is therefore possible to obtain the X and Y area scaleshaving an accurate pitch and perpendicularity and the XY crosshatch thataccurately aligns with the axial directions of the area scales and thusobtain accurate coordinates.

Note that in this embodiment, a skew detecting sensor 273 is provided soas to maintain the position management accuracy even if a small skew ormeandering (complex skew) occurs in the position management plane stage220. In the examples shown in (8 b) and (8 c) of FIG. 8, a skew isdetected in the X-axis direction. The skew detecting sensor 273 isimplemented at a predetermined interval in the Y direction of theattached position of the X-axis sensor 271. The longer the intervalbetween the X-axis sensor 271 and the skew detecting sensor 273 is, thehigher the accuracy is. Hence, the two sensors are arranged within themovable range of the stage as far as possible unless they are off the Xarea scale 211. Note that the skew may be detected in the Y-axisdirection. In that case, the skew detecting sensor 273 is implemented ata predetermined interval in the X direction of the attached position ofthe Y-axis sensor 272. Since the orthogonality between the X area scale211 and the Y area scale 212 is guaranteed to be accurate by the formingmethod, detecting a skew in one of the X and Y directions suffices.

Note that as each of the X-axis sensor 271 and the Y-axis sensor 272, adetection sensor described in Japanese Patent Application No.2014-079401 by the same applicant is usable. When this detection sensorand an accurate area scale by nanotechnology are used, for example, aresolution of 10 nm (0.01 μm) or less is obtained by a 1/2000interpolation operation with respect to the accurate scale having awidth of 2 μm and a pitch of 4 μm, and a position (management) accuracyof 0.1 μm can be implemented. This is merely an example, as a matter ofcourse. Another commercially available detection sensor using an opticallens may be used as each of the X-axis sensor 271 and the Y-axis sensor272, and a resolution of 10 nm (0.01 μm) or less and a position(management) accuracy of 0.1 μm may be implemented by a knowninterpolation operation. The scale shown in (7 c) of FIG. 7 is anexample of an incremental type. However, it may be an absolute type.That is, an encoder (scale and sensor) of any type is employable as longas a predetermined accuracy is obtained. Note that the Y area scale 212has a scale pattern obtained by rotating the X area scale 211 by 90°around the Z-axis. The X area scale may include Y-axis information, orconversely, the Y area scale may include X-axis information.

In FIG. 9, (9 a) and (9 b) show the positional relationship between theX-axis sensor 271, the Y-axis sensor 272, and the skew detecting sensor273 and the X area scale 211 and the Y area scale 212. This relationshipis the same for both the sensor arrangement by the above-described firstmethod and the sensor arrangement by the second method.

In FIG. 9. (9 a) shows the positional relationship between the sensorsand the scales in a case in which the observation position by themicroscope, that is, the center of the observation field 170(illustrated much larger than the size of the actual observation field)of the microscope is located at the crosshatch origin, that is, the XYcoordinate origin (stage origin 206) of the stage. In this case, theposition management plane stage 220 is located at the lower left end(the left end and the far end) with respect to the microscope base stand121. On the other hand, (9 b) of FIG. 9 shows the positionalrelationship between the sensors and the scales in a case in which theobservation position by the microscope, that is, the center of theobservation field 170 is located at the lower left corner of theobservation object region 205. In this case, the position managementplane stage 220 is located at the upper right end (the right end and thenear end) with respect to the microscope base stand 121.

Sizes needed by the X area scale 211 and the Y area scale 212 can beknown from (9 a) and (9 b) of FIG. 9. That is,

-   -   the X area scale 211 needs a size obtained by adding a size to        include the X-direction moving amount of the observation object        region 205 with an allowance and the same size for skew        detection, that is, a size about twice larger than the size of        the observation object region 205, and    -   the Y area scale 212 needs a size to include the Y-direction        moving amount of the observation object region 205 with an        allowance, that is, almost the same size as the observation        object region 205.

However, when detecting a skew in the Y direction, the Y area scale 212needs a size about twice larger than the size of the observation objectregion, and the X area scale 211 needs a size to include the X-directionmoving amount of the observation object region 205 with an allowance.

If each of the X-axis sensor, the Y-axis sensor, and the skew detectingsensor includes a plurality of sensors, and detection is relayed by thesensors, the size of each area scale can be reduced. This enablesdownsizing of the position management plane stage 220. In FIG. 10, (10a) and (10 b) show an example in which each sensor includes two sensors.Note that in this example, a plurality of sensors configured to do relayare arranged for each of the X-axis sensor and the Y-axis sensor.However, a plurality of sensors configured to do relay may be arrangedfor one of the X-axis sensor and the Y-axis sensor.

Referring to (10 a) and (10 b) of FIG. 10, an X-axis intermediate sensor271 a, a Y-axis intermediate sensor 272 a, and a skew detectingintermediate sensor 273 a are arranged at the intermediate positions(positions at which the X- and Y-direction moving amounts are halved) tothe X-axis sensor 271, the Y-axis sensor 272, and the skew detectingsensor 273, respectively. In FIG. 10, (10 a) shows a case in which thecenter of the observation field 170 is located at the crosshatch origin,that is, the stage origin 206. In FIG. 10, (10 b) shows a case in whichthe center of the observation field 170 is located at the lower leftcorner of the observation object region 205. As is apparent from FIGS. 9and 10, when relay by the intermediate sensors is performed, the X areascale 211 can have a size about ½ in the X direction, and the Y areascale 212 can have a size about ½ in the Y direction. That is, theX-axis sensor 271 and the X-axis intermediate sensor 271 a are arrangedat a predetermined interval along the X-axis direction, and the size ofthe X area scale 211 in the X-axis direction is slightly larger than thepredetermined interval but can be made smaller than the moving range ofthe XY stage in the X-axis direction. This also applies to a case inwhich the Y-axis intermediate sensor 272 a is provided. Hence, the sizeof the XY two-dimensional scale plate 210 can be reduced as compared toa case in which each of the X-axis sensor 271 and the Y-axis sensor 272includes one sensor.

The XY crosshatch 213 provided on the XY two-dimensional scale plate 210will be described next. In FIG. 11, (11 a) and (11 b) are views forexplaining the pattern of the XY crosshatch 213. As shown in (11 a) ofFIG. 11, the XY crosshatch 213 includes four types of position referencemarks, that is, a crosshatch 290, a crosshatch origin 291, a crosshatchX-axis 292, and a crosshatch Y-axis 293. The crosshatch X-axis 292 andthe crosshatch Y-axis 293 are linear patterns extending in the Xdirection and the Y direction, respectively.

The crosshatch origin 291 is used as the stage origin 206 (the stagereference position used to obtain coordinates based on the stage origin)by setting (replacing) the center of the observation field 170 of themicroscope located at the crosshatch origin 291 as the origin of the X-and Y-coordinates of the stage. Note that in FIG. 11 and the like, theobservation field 170 is illustrated much larger than the size of theactual observation field. The center of the observation field 170 is thefield center (the center of the objective lens 148), that is, the centerof the image sensor 401. The stage origin 206 is located at the upperright corner of the observation object region 205 (the region in whichthe center of the objective lens 148 moves). The crosshatch 290, thecrosshatch X-axis 292, and the crosshatch Y-axis 293 are the referencesof the X-axis and the Y-axis of the stage 200. The parts of the stage200 are assembled so as to be aligned with the X-axis and the Y-axis ofthe XY crosshatch 213, or adjusted after assembled. That is, the partsare assembled such that the X and Y moving directions (the stage X-axis203 and the stage Y-axis 204) of the stage 200 accurately align with theX and Y directions of the XY crosshatch 213. The X and Y movingdirections of the stage 200 thus align with the X-axis direction of theX area scale 211 and the Y-axis direction of the Y area scale 212,respectively. The XY crosshatch 213 arranged at a position on the XYtwo-dimensional scale plate 210 observable by the digital camera 400 canthus be used for XY-axis alignment between the stage 200 and the imagesensor 401 of the digital camera 400 as the reference of the X-axis andthe Y-axis of the stage. Note that when attaching the stage 200 to themicroscope body 100, the XY crosshatch 213 can also be used to align theX- and Y-axes of the stage 200 with the X- and Y-axes of the microscopebase stand 121.

As will be described later, in the microscope system according to thisembodiment, the X- and Y-axis directions of the stage 200 and the X- andY-axis directions of the slide 700 placed on the stage 200 areaccurately aligned via the image sensor 401. This enables universalposition management without any influence of a positional shift thatoccurs when one slide is replaced and observed or a stage characteristicbetween different digital microscopes. More specifically,

-   -   the X- and Y-axis directions of the stage 200 and those of the        image sensor 401 are aligned based on an image (either a still        image or a moving image) obtained by capturing the XY crosshatch        213 by the digital camera 400, and    -   the X- and Y-axis directions of the slide 700 and those of the        image sensor 401 are aligned based on an image (either a still        image or a moving image) obtained by capturing the Y-axis mark        of the slide 700 using the digital camera 400, thereby aligning        the X- and Y-axis directions of the stage 200 with the X- and        Y-axis direction of the slide 700 placed on the stage 200.        Details of processing will be described later.

In FIG. 11, (11 b) shows a detailed example of the dimensionalrelationship between the four marks, that is, the crosshatch origin 291,the crosshatch X-axis 292, the crosshatch Y-axis 293, and the crosshatch290. The crosshatch X-axis 292 is a complex of a plurality of X-axislines having different widths, and the crosshatch Y-axis 293 is acomplex of a plurality of Y-axis lines having different widths. Thecrosshatch X-axis 292 and the crosshatch Y-axis 293 have axisinformation in the X-axis direction and axis information in the Y-axisdirection, respectively. Note that the widths of the lines correspond tothe objective lenses with a plurality of magnifications. That is, eachof the crosshatch X-axis 292 and the crosshatch Y-axis 293 is formedfrom a plurality of lines with different widths. The plurality of linesare line patterns arranged to be symmetric with respect to the centerline (X-axis or Y-axis). Note that the crosshatch 290 employs a patternas shown in (11 b) of FIG. 11 to avoid the lines in the X-axis directionand the lines in the Y-axis direction from intersecting, but may employa general crosshatch pattern in which the lines in the X-axis directionand the lines in the Y-axis direction intersect, that is, a pattern asshown in (11 a) of FIG. 11. The crosshatch origin 291 is arranged suchthat its center aligns with the intersection between the center line ofthe crosshatch X-axis 292 and that of the crosshatch Y-axis 293. In thisembodiment, an X initial position mark 234 ((18 b) of FIG. 18) and a Yinitial position mark 253 ((19 b) of FIG. 19) (both will be describedlater) are implemented at a predetermined accuracy according to thecrosshatch origin 291.

In FIG. 12, (12 a) and (12 b) show a more detailed example of thestructure of the crosshatch Y-axis 293. In FIG. 12, (12 b) is anenlarged view of the central portion of (12 a) of FIG. 12. Thecrosshatch Y-axis 293 has a structure in which, for example, a pluralityof pairs of lines with the same width are arranged to be symmetric withrespect to the center line serving as the axis of symmetry whilechanging the width. Note that a certain line may exist on the centerline. In addition, the relationship between lines and spaces may bereversed. Accordingly, in both the angle of view at a low magnificationof the objective lens and the angle of view at a high magnification, anappropriate number of lines with appropriate widths are captured by thelive image capturing function or the still image capturing function, anda predetermined accuracy is ensured in barycentric detection (to bedescribed later). The crosshatch X-axis 292 has a structure obtained byrotating the crosshatch Y-axis 293 by 90°. The intervals of the centerlines of the lines or spaces of the crosshatch X-axis 292 and thecrosshatch Y-axis 293, the intervals of the boundaries (edges) betweenthe lines and spaces, the widths of the lines or spaces, and the likeare set to predetermined values and are useful as actual distanceinformation. Each line may further be formed from an aggregate of pairsof fine lines and spaces. The width of the fine line is set to, forexample, 1/10 or less of the width of the narrowest line out of theplurality of lines that form the mark (for example, 1 μm). This enablesinclusion of finer actual distance information.

The crosshatch 290 is formed by, for example, arranging, in the Xdirection and the Y direction at a pitch of 1 mm, small crosshatcheseach including two X-axis lines and two Y-axis lines which are 0.5 mmlong each and are alternately arranged within a 1 mm square. In FIG. 12,(12 c) shows a detailed example of the structure of the smallcrosshatch. The 0.5 mm long X- and Y-axis lines of the small crosshatchare larger than the field size (for example, 0.37 mm) of a 40× objectivelens. Only an X-axis line or Y-axis line can be observed in anappropriate width within the visual field, and accurate positioninformation can be obtained by barycentric detection. The crosshatch 290is useful for adjustment or maintenance of the stage moving accuracy.The crosshatch 290 can also be used to measure a geometric distortion(mainly caused by the optical system of the objective lens) on theperiphery of the observation field 170. The measured distortion can beused for distortion correction of a captured image. Note that theintervals between the reference marks included the XY crosshatch 213,the sizes of the reference marks, the structures of the reference marks,the intervals of the center lines of the lines or spaces of thereference marks, the intervals of the boundaries (edges) between thelines and spaces, the widths of the lines or spaces, and the like areset to predetermined values and are useful as actual distanceinformation. Note that a general crosshatch pattern as shown in (11 a)of FIG. 11 may be used as the small crosshatch. In this case, manyvariations are possible, and for example, the grid size mayappropriately be selected, a plurality of crosshatches of different gridsizes may be provided, or the grid lines of the crosshatch may be formedfrom complex lines, like the crosshatch X-axis 292 and the crosshatchY-axis 293. Note that as shown in (11 b) of FIG. 11, all of the sizes ofthe reference marks, the distances between them, and the like are morethan the field size of, for example, a 10× objective lens, that is, 1.5mm. That is, to efficiently detect the mark positions, the positionreference marks are disposed at intervals equal to or more than adistance equivalent to the field size (in this embodiment, equal to ormore than the field size (1.5 mm) of the 10× objective lens) so as notto simultaneously observe adjacent position reference marks within thesame visual field of the microscope. Note that the crosshatch origin 291may also include fine lines (for example, white lines and black lineswhich are 1 μm wide each and are alternately arranged), like thecrosshatch X-axis 292 and the crosshatch Y-axis 293.

Note that the XY two-dimensional scale plate 210 having the integralstructure need not always be used if the X area scale 211, the Y areascale 212, and the XY crosshatch 213 can maintain the accuracy in theaxial directions of the XY stage and the accuracy of the orthogonalitybetween the X-axis direction and the Y-axis direction. However, if astructure in which the Y area scale configured to detect a Y-directionposition is arranged on the Y stage, and the X area scale configured todetect an X-direction position is arranged on the X stage, like ageneral XY stage in which a linear (uniaxial) scale configured to detecta Y-direction position is arranged on the Y stage, and a linear(uniaxial) scale configured to detect an X-direction position isarranged on the X stage, is employed, an advanced machining techniqueand alignment technique are required to maintain the above-describedaccuracies. This may lead to an increase in the cost of the microscope.

The arrangement of the ΔΘ stage 600 disposed on the position managementplane stage 220 will be described next with reference to FIGS. 13 to 17.The position management plane stage 220 is the stage in the uppermostportion of the stage 200, and moves the Y stage 240 configured to movein the Y direction in the X direction, thereby moving the Y stage 240 inthe X and Y directions. The ΔΘ stage 600 includes a rotary stage 691that rotates around the Z-axis around a rotation center 601. The ΔΘstage 600 aims at correcting the rotational shift of the slide and theslant (tilt) of the upper surface of the slide with respect to theoptical axis, which occur when placing the slide, without distinctionbetween automatic loading and manual loading of the slide, and attainingthe above-described target position management accuracy of ±0.1 μm forthe observation position in each of the X, Y, and Z directions of threedimensions.

In FIG. 13, (13 a) is a perspective view of the position managementplane stage 220 viewed from the upper surface side, and shows a state inwhich the ΔΘ stage 600 is incorporated in the position management planestage 220. In FIG. 13, (13 b) is a perspective view of the positionmanagement plane stage 220 viewed from the lower surface side, and showsa state in which the ΔΘ stage 600 is fixed to the position managementplane stage 220 via dZ lift units 650. As will be described later indetail, an attachment plate 651 of each dZ lift unit 650 is fixed to theposition management plane stage 220 by screws 651 a. In addition, springholding plates 652 are fixed to the ΔΘ stage 600 by screws 652 a, and aleaf spring 656 (FIGS. 15 and 16) is held between the spring holdingplates 652 and the position management plane stage 220, therebymaintaining the pressed state of the ΔΘ stage 600 against the dZ liftunit 650. The ΔΘ stage 600 is thus mounted on the position managementplane stage 220 via the dZ lift units 650.

In FIG. 14, (14 a) and (14 b) are perspective views of the ΔΘ stage 600viewed from the lower surface side and the upper surface side (the sideof the surface on which the slide 700 is placed), respectively. In (14a) and (14 b) of FIG. 14, the ΔΘ stage 600 includes a ΔΘ base 692 and aΔΘ cover 693, and has a structure in which the rotary stage 691 ismounted on the ΔΘ base 692. A dZ scale 640 is provided on a side surfaceof the ΔΘ cover 693. In FIG. 14, (14 c) shows a state in which the ΔΘcover 693 is removed from the ΔΘ stage 600. The rotary stage 691 ismounted on the ΔΘ base 692 to be pivotal around the rotation center 601,and pivots as a rotation driving mechanism 694 is driven. The ΔΘ base692 is fixed to the position management plane stage 220 via the dZ liftunits 650. As shown in (14 c) of FIG. 14 and the like, the dZ lift units650 connect the ΔΘ stage 600 and the position management plane stage 220at a plurality of points, in this example, three points, and move the ΔΘstage 600 independently in the Z direction. Of lift pins 654 (dZ1 todZ3) of the three dZ lift units 650, two lift pins (dZ1 and dZ2) arearranged on the microscope base stand side at positions along the X-axisdirection, and the remaining one lift pin (dZ3) is arranged on the farend side with respect to the microscope base stand so as to form anisosceles triangle. A dZ sensor 641 configured to read the dZ scale 640is provided on the position management plane stage 220 at a positionfacing the dZ scale 640.

In FIG. 15, (15 a) to (15 d) are views showing the dZ lift unit 650according to the embodiment. The attachment plate 651 extends to thelower surface of the position management plane stage 220, and is fixedto the position management plane stage 220 by the screws 651 a. Thespring holding plates 652 are fixed to the lower surface of the ΔΘ base692 by the screws 652 a. A motor flange 657 integrated with a dZ motor653 is fixed to the attachment plate 651. The dZ motor 653 is thus fixedto the attachment plate 651. A lift pin guide 658 is fixed to theattachment plate 651 such that the leaf spring 656 as an elastic memberand the motor flange 657 are sandwiched between them. The rotating shaftof the dZ motor 653 is provided with the lift pin 654 that comes intocontact with a spherical bearing 655 press-fitted in the lower surfaceof the ΔΘ base 692. As described above, the dZ scale 640 is provided ona side surface of the ΔΘ stage 600, and the dZ sensor 641 is provided ata corresponding position on the position management plane stage 220.

As shown in (15 e) of FIG. 15, the dZ scale 640 includes a dZ initialposition mark 640 a and a dZ linear scale 640 b. The dZ sensor 641includes a dZ initial position sensor 641 a and a dZ-axis sensor 641 b.The dZ initial position sensor 641 a detects the dZ initial positionmark 640 a, and the dZ-axis sensor 641 b reads the dZ linear scale 640b. By the dZ scale 640 and the dZ sensor 641, the moving amount of theΔΘ stage 600 in the vertical direction is managed, and accurate tiltcorrection of the upper surface of the slide 700 is implemented. Notethat the dZ linear scale 640 b has the same pattern as that of the Xarea scale 211 ((7 c) of FIG. 7, and the like), and is formed as alinear scale with a narrower scale width. Like the X area scale 211, thedZ linear scale 640 b includes, for example, transmission parts andlight-shielding parts, each of which is a line having a width of 2 μm.The transmission parts and the light-shielding parts are disposed inpairs at a pitch of 4 μm. Using the dZ linear scale 640 b and thedZ-axis sensor 641 b, a resolution of 10 nm (0.01 μm) or less and aposition accuracy of 0.1 μm are implemented by, for example, a 1/2000interpolation operation. The Z-direction movable range of the ΔΘ stage600 by the dZ lift unit 650 is about ±0.2 mm with respect to the dZinitial position mark 640 a as the center. However, the presentinvention is not limited to this.

In FIG. 16, (16 a) is a view showing a state in which the positionmanagement plane stage 220 and the ΔΘ base 692 are connected by the dZlift unit 650. As described above, the attachment plate 651 is fixed tothe position management plane stage 220 by the screws 651 a. The springholding plates 652 are fixed to the ΔΘ base 692 by the screws 652 a. InFIG. 16, (16 b) shows a section taken along a line F-F in (16 a), and(16 c) shows a section taken along a line E-E in (16 a). When the ΔΘbase 692 is biased downward in the Z-axis direction by the leaf spring656, the ΔΘ base 692 (spherical bearing 655) is pressed against the liftpin 654, and the ΔΘ stage 600 is stably fitted in the positionmanagement plane stage 220. The rotating shaft of the dZ motor 653includes a screw portion 659. When the dZ motor 653 is driven, the liftpin 654 moves in the rotation axis direction. The lift pin 654 isbrought into contact with the spherical bearing 655 incorporated in thelower surface of the ΔΘ base 692 by the biasing force of the leaf spring656. When the lift pin 654 moves up and down (moves in the rotation axisdirection of the dZ motor 653), the ΔΘ stage 600 moves up and down.

The arrangement and rotational shift correction of the rotary stage 691of the ΔΘ stage 600 will be described next. The worst value of therotational shift of the slide is assumed to be about ±0.5 mm at an end,which is equivalent to a rotational shift of about ±0.4° (±0.38°). Thisstate is shown in (17 c) of FIG. 17. To correct the rotational shift ofthe slide, the slide is rotated by the rotary stage 691 of the ΔΘ stage600 and corrected to a vertical error (tangent error or TAN error) of±0.1 μm (about ±0.1 millidegree) within the observable range (56 mm).Note that practically, if the vertical error can be suppressed to ±0.1μm (about ±3 millidegrees) or less at the two ends of a 2 mm observationrange, a level more than enough for pathological diagnosis is expectedto be obtained. A range of about ±20 to ±3° is sufficient as the maximummovable range of the rotary stage 691.

In (17 a) of FIG. 17, a slide holder 602 that defines the placementposition of a slide is disposed on the rotary stage 691 of the ΔΘ stage600, and the slide 700 with position references is placed. A lever 604provided on the slide holder 602 has a function of pressing the slide700 against reference positions 603 of the slide holder 602. The slide700 is thus stably placed.

The rotary stage 691 can slidably rotate within the XY plane of the ΔΘstage 600 around the rotation center 601 fixed to the ΔΘ base 692 as therotation axis, and is rotated by the rotation driving mechanism 694. Therotation driving mechanism 694 is implemented in the ΔΘ stage 600, asshown in, for example, (17 a) and (17 b) of FIG. 17, and includes a ΔΘdriving motor 611, a screw shaft 612 of a ball screw, and a nut portion613 of the ball screw. The screw shaft 612 is a member disposed at thedistal end of the rotating shaft of the ΔΘ driving motor 611, and thenut portion 613 is a member that moves in the screw shaft direction inaccordance with the rotation of the screw shaft 612 of the ball screw.When the ΔΘ driving motor 611 is rotated, the screw shaft 612 rotates,and a driving linear gear 614 attached to the nut portion 613 moves. Forthis reason, a driven arc gear 615 as the counterpart of fittingattached to an end of the rotary stage 691 moves. As a result, therotary stage 691 rotates around the rotation center 601 together withthe placed slide, and the rotational error of the slide is corrected. InFIG. 17, (17 b) shows a state in which the slide 700 (rotary stage 691)is rotated clockwise by an angle θ from the state shown in (17 a) ofFIG. 17. Note that the rotational driving of the rotary stage 691 can bedone not only by the above-described combination of a driving motor, aball screw, and gears but also by, for example, ultrasonic driving usingfriction caused by a moving element and a driving motor.

In addition, a ΔΘ initial position mark 620 used for initialization atthe time of activation is attached to the end of the rotary stage 691,and defines the initial position of the rotary stage 691. A ΔΘ initialposition sensor 621 is provided on the side of the ΔΘ base 692 so as toface the ΔΘ initial position mark 620, and detects the initial positionof the rotary stage 691 at the time of activation. If the initialposition is used as a reference position in a case without a rotationalshift of the slide, rotating the ΔΘ stage 600 within the range of, forexample, ±2° to ±3° to each side of the reference position suffices.Control of the ΔΘ stage 600 will be described later.

The position management plane stage 220, the Y stage 240, and the stagebase 260, which constitute the XY stage of the stage 200 according tothis embodiment, will be described next in detail. Note that thestructure of each stage in a case in which the sensor arrangement method(the method of arranging the X-axis sensor 271, the Y-axis sensor 272,and the skew detecting sensor 273 on the stage base 260) explained withreference to (8 c) of FIG. 8 is used will be described below. However,the structures and the like in a case in which the sensor arrangementmethod shown in (8 b) of FIG. 8 is used can also be known from thefollowing explanation.

The position management plane stage 220 will be described first withreference to FIG. 18. In FIG. 18. (18 a) is a top view of the positionmanagement plane stage 220 (viewed from the objective lens side), and(18 b) is a bottom view of the position management plane stage 220(viewed from the side of the Z base 130). In this embodiment, theposition management plane stage 220 has the function of an X stage thatmoves in the X direction on the Y stage 240.

Openings 221 and 222 that allow the X-axis sensor 271, the Y-axis sensor272, and the skew detecting sensor 273 to access the area scales areprovided at positions corresponding to the X area scale 211 and the Yarea scale 212 of the XY two-dimensional scale plate 210. The openings221 and 222 have sizes to include the X area scale 211 and the Y areascale 212, respectively.

An opening 223 is provided in a range in which a condenser lens opening224 relatively moves on the position management plane stage 220 when thecenter of the condenser lens opening 224 (having a size larger than thesize of a condenser lens unit incorporating the condenser lens 147 so asto form an allowance) moves relative to the XY stage throughout theobservation object region 205. Because of the opening 223, the condenserlens unit (the housing incorporating the condenser lens) neverinterferes with the position management plane stage 220 no matter wherethe position management plane stage 220 moves in the observation objectregion 205.

Two X-axis cross roller guides 231 are disposed on the lower side of theposition management plane stage 220 so as to be parallel to the X-axisdirection. X-axis cross roller guides 241 (FIG. 19) are attached to theupper surface of the Y stage 240 so as to face the X-axis cross rollerguides 231. The position management plane stage 220 is thus supported bythe Y stage 240 to be slidable in the X direction. An X slider 232 isthe movable element of an X-axis driving motor 242 (FIG. 19)incorporated in the opposing surface of the Y stage 240. The positionmanagement plane stage 220 is driven in the X-axis direction by theX-axis driving motor 242. That is, the X-axis driving motor 242 and theX slider 232 form a linear motor by, for example, an ultrasonic wave.

An X-axis rack gear 233 moves the position management plane stage 220 inthe X direction along with the rotation of an X-axis pinion gear 244 onthe Y stage 240 that rotates in synchronism with the X knob 201. Notethat the manual movement of the position management plane stage 220 inthe X direction can be done not only by the rack and pinion but also by,for example, a wire and pulley method. At any rate, in this embodiment,the position management plane stage 220 can be moved in the X directionby both the manual driving means and the electric driving means.

In this embodiment, the X initial position mark 234 corresponds to theX-direction position of the crosshatch origin 291 serving as the XYcoordinate origin (stage origin 206) of the stage 200 at a predeterminedaccuracy. That is, in this embodiment, the X initial position mark 234is implemented on the extension of the center line of the crosshatchY-axis 293 passing through the crosshatch origin 291 of the XYcrosshatch 213 at a predetermined accuracy. Note that the initializationposition of the stage on the mechanism may be another position. Thestage origin 206 is defined by a case in which the sensor center of thecamera aligns with the crosshatch origin 291 independently of theinitialization position of the stage on the mechanism. That is, theinitialization position of the stage 200, that is the disposing positionof the X initial position mark 234 need not always be aligned with thecrosshatch origin 291 or the stage origin 206.

The Y stage 240 will be described next with reference to FIG. 19. InFIG. 19, (19 a) is a top view of the Y stage 240 (viewed from the sideof the position management plane stage 220), and (19 b) is a bottom viewof the Y stage 240 (viewed from the side of the Z base 130).

In (19 a) of FIG. 19, the X-axis cross roller guides 241 are paired withthe X-axis cross roller guides 231 disposed on the lower surface of theposition management plane stage 220 and support the position managementplane stage 220 slidably in the X-axis direction. The X-axis drivingmotor 242 moves the position management plane stage 220 in the Xdirection via the X slider 232 of the position management plane stage220. The X-axis pinion gear 244 meshes with the X-axis rack gear 233provided on the lower surface of the position management plane stage220, and moves the position management plane stage 220 in the X-axisdirection by rotation. Since the X-axis pinion gear 244 rotates inaccordance with the rotation of the X knob 201, the user can move theposition management plane stage 220 in the X-axis direction by operatingthe X knob 201. An X initial position sensor 243 detects the X initialposition mark 234 provided on the lower surface of the positionmanagement plane stage 220.

An opening 245 is an opening that causes the X-axis sensor 271 and theskew detecting sensor 273 arranged on the stage base 260 to access the Xarea scale 211 via the opening 221 of the position management planestage 220. Since the Y stage 240 moves in the Y direction out of the Xand Y directions relative to the stage base 260, the opening 245 has ashape extending in the Y direction. Similarly, an opening 246 is anopening that causes the Y-axis sensor 272 provided on the stage base 260to access the Y area scale 212 via the opening 222 of the positionmanagement plane stage 220. An opening 247 corresponds to a region inwhich condenser lens opening 224 moves in a case in which the center(also serving as the center of the condenser lens 147) of the condenserlens opening 224 (having a size larger than the size of the condenserlens unit incorporating the condenser lens 147 so as to form anallowance) moves in the observation object region 205. As describedabove, since the Y stage 240 moves in the Y direction out of the X and Ydirections, the opening 247 has a shape extending not in the X-axisdirection but in the Y-axis direction. Because of the opening 247, the Ystage 240 never interferes with the condenser lens unit even when movedin the Y direction of the observation object region 205.

Two Y-axis cross roller guides 251 are disposed on the lower surface ofthe Y stage 240 ((19 b) of FIG. 19) so as to be parallel to the Y-axis.Cross roller guides paired with the Y-axis cross roller guides 251 areattached to the stage base 260. The Y stage 240 is thus supported by thestage base 260 to be slidable in the Y direction. A Y slider 252 is themovable element of a Y-axis driving motor 264 (FIG. 20) incorporated inthe opposing surface of the stage base 260. The Y stage 240 is driven inthe Y-axis direction by the Y-axis driving motor 264. The Y-axis drivingmotor 264 and the Y slider 252 form a linear motor by, for example, anultrasonic wave.

A Y-axis pinion gear 254 rotates along with the rotation of the Y knob202. As the Y knob 202 rotates, the Y-axis pinion gear 254 moves aY-axis rack gear 263 (FIG. 20) fixed on the stage base 260 in the Y-axisdirection. Hence, the user can manually move the Y stage 240 in theY-axis direction by operating the Y knob 202. Note that the manualmovement of the stage in the Y direction can be done not only by therack and pinion but also by, for example, a wire and pulley method. Atany rate, in this embodiment, the Y stage 240 can be moved in the Ydirection by both the manual driving means and the electric drivingmeans. The Y stage 240 moves in the Y direction relative to the stagebase 260 while supporting the position management plane stage 220. Inthis embodiment, the Y initial position mark 253 corresponds to theY-direction position of the crosshatch origin 291 serving as the XYcoordinate origin (stage origin 206) of the stage 200 at a predeterminedaccuracy. That is, in this embodiment, the Y initial position mark 253is implemented on the extension of the center line of the crosshatchX-axis 292 passing through the crosshatch origin 291 of the XYcrosshatch 213 at a predetermined accuracy. Note that the initializationposition of the stage on the mechanism may be another position. Thestage origin 206 is defined by a case in which the sensor center of thecamera aligns with the crosshatch origin 291 independently of theinitialization position of the stage on the mechanism. That is, theinitialization position of the stage 200, that is, the disposingposition of the Y initial position mark 253 need not always be alignedwith the crosshatch origin 291 or the stage origin 206.

The stage base 260 will be described next with reference to FIG. 20.FIG. 20 is a top view of the stage base 260 (a view showing the stagebase 260 viewed from the side of the Y stage 240). The X-axis sensor 271and the skew detecting sensor 273 which are configured to read the Xarea scale 211 and the Y-axis sensor 272 configured to read the Y areascale 212 are attached on the stage base 260. The heights of the sensorsare adjusted by a base (not shown) to obtain predetermined distances tothe X area scale 211 and the Y area scale 212 of the XY two-dimensionalscale plate 210 provided on the position management plane stage 220. Asdescribed above, the X-axis sensor 271 is provided on the X-axis passingthrough the stage origin 206 (crosshatch origin 291), and the Y-axissensor 272 is provided on the Y-axis passing through the stage origin206. The skew detecting sensor 273 is implemented at a predeterminedinterval in the Y direction of the attached position of the X-axissensor 271.

Y-axis cross roller guides 262 are paired with the Y-axis cross rollerguides 251 disposed on the lower surface of the Y stage 240 and supportthe Y stage 240 slidably in the Y-axis direction. The Y-axis drivingmotor 264 is a motor configured to electrically move the Y stage 240 (Yslider 252) in the Y direction. The Y-axis rack gear 263 moves the Ystage 240 in the Y direction in accordance with the rotation of theY-axis pinion gear 254. A Y initial position sensor 265 detects the Yinitial position mark 253 provided on the lower surface of the Y stage240. An opening 261 corresponds to the condenser lens opening 224(having a size larger than the size of the condenser lens unitincorporating the condenser lens 147 so as to form an allowance).Because of the opening 261, the condenser lens unit never interfereswith the stage base 260. Note that as described above with reference toFIG. 4, the stage base 260 is provided with the spring hooks 995, thespherical bearings 996, and the sensor plate holes 997 used to mount thestage base 260 on the ΔZ stage 900. The stage base 260 is also providedwith the Z base attachment holes 902 a and the positioning holes 903 awhich allow the stage base 260 to be directly fixed on the Z base 130.

The openings 261, 247, and 223 allow the condenser lens unit to approachthe observation position on the slide from the lower side of the slide,and also pass source light condensed by the condenser lens 147.

The sizes of the openings for the X-axis sensor 271, the Y-axis sensor272, the skew detecting sensor 273, and the condenser lens 147 providedin the above-described stages can be large to some extent as long as themechanical strength and accuracies are maintained.

The adapter unit 300 configured to connect the eyepiece base 122 and thedigital camera 400 will be described next. The image sensor 401 (FIG. 2)is an area sensor (camera sensor) in which pixels each formed from, forexample, a CMOS element are arrayed in a matrix, that is, in the rowdirection (X direction) and the column direction (Y direction), and hasX- and Y-axes. Generally, in the microscope, the X and Y-axes(determined by the optical system of the split prism 150 and theeyepiece barrel 123 (FIG. 2)) of the observation optical system areassembled in accordance with the X-axis of the microscope base stand121. The XY stage is also attached via the Z base 130 at a predeterminedaccuracy in accordance with the X-axis of the microscope base stand 121.Hence, if the X-axis of the image sensor 401 has a rotational shift withrespect to the X-axis of the eyepiece barrel 123 (=the X-axis of themicroscope base stand 121), the X- and Y-axes have a rotational shiftwith respect to the X- and Y-axes of an eyepiece observation image andthe X- and Y-axes of the stage.

The digital camera 400 is attached to the adapter unit 300 via a lensmount with a positioning pin. The adapter unit 300 is attached to theeyepiece base 122 by screwing with a positioning pin. The positioningpin is assumed to always produce a slight rotational shift because ofits mechanical accuracy. FIG. 44 shows views for explaining theinfluence of a rotational shift between the X- and Y-axes of a capturedimage (the X- and Y-axes of the image sensor 401) and the X- and Y-axesof the stage. The views are exaggerated to some extent for thedescriptive convenience. For example, as shown in (44 a) of FIG. 44,when the stage 200 is moved in the X-axis direction, and an entire ROIis captured as two adjacent images 2001 and 2002, the images arecaptured obliquely alike due to the rotational shift.

On the other hand, the captured images 2001 and 2002 (evidence images)are displayed using the X-axis of the image sensor as the horizontalaxis, as shown in (44 b) of FIG. 44. Referring to (44 b) of FIG. 44,reference numeral 2011 denotes a field center which aligns with thecenter of the image sensor 401. Reference numeral 2012 assumes an objectof interest in the ROI area and indicates the same object in the images2001 and 2002. However, because of the above-described rotational shift,the Y-coordinate value changes between the images 2001 and 2002 that areadjacent on the left and right. This means that the coordinate values oneach evidence image are different from position coordinates by thestage. In particular, assuming a case in which the ROI is large, and theentire ROI area covers the whole tissue slice area on the slide, thismeans that the coordinates of the observation position based on the X-and Y-axes of the sensor largely shift from the coordinate values basedon the X- and Y-axes of the stage. From the viewpoint of positionmanagement, the coordinates of a point of interest on the evidence imagebased on the X- and Y-axes of the sensor are preferably the same as thecoordinates based on the X- and Y-axes of the stage. The target accuracyof the degree of alignment is the same as the target of positionmanagement by the above-described XY stage, that is, 0.1 μm (in steps of0.01 μm).

In addition, when the controller 501 composes the two images to generatethe evidence image of the entire ROI, rotation correction by imageprocessing is necessary. However, the amount of the rotational shift isunknown, the degree of difficulty in accurately connecting images byimage recognition processing is high, and rotation calculationprocessing normally causes degradation in image quality. However, if therotational shift falls within the position management target of 0.1 μm,the two images can accurately be connected by simple translation. Theadapter unit 300 according to this embodiment includes a mechanismconfigured to align the X- and Y-axes of the image sensor 401 with theX- and Y-axes of the stage 200 (XY stage), and thus copes with theabove-described problem.

FIG. 21 is a view showing the structure of the adapter unit 300. Ingeneral, the microscope body 100 and the digital camera 400 aremanufactured by different makers. In consideration of compatibilitybetween products of different makers, the adapter unit 300 has a threebody structure including an optical adapter 320 that is a first adapterunit, a ΔC adapter 340 that is a second adapter unit, and a cameraadapter 360 that is a third adapter unit. This is because since the basemount 128 of the eyepiece base 122 complies with a standard unique to amicroscope maker, and the camera mount of the digital camera 400complies with a standard unique to a camera maker, it is preferable toprovide the ΔC adapter 340 with a new mount as a new common standard.

Note that the base mount 128 on the eyepiece base 122 shown in FIG. 21,which complies with the standard unique to the microscope maker,generally only aims at fixing the optical adapter, and the position inthe rotation direction is indefinite. In this embodiment, however, thebase mount 128 includes a mount that is newly given a positioningreference hole 311 such that the rotation positions of the eyepiece base122 and the optical adapter have a predetermined positionalrelationship. In correspondence with this, generally, a base stand-sidemount 321 of the optical adapter 320 whose position in the rotationdirection is indefinite is also newly given a positioning referenceprojection 322. When the optical adapter 320 is mounted by fitting thereference projection 322 in the positioning reference hole 311 of thebase mount 128, the position of the optical adapter 320 in the rotationdirection (the fitting position to the positioning reference hole 311)is uniquely determined with respect to the eyepiece base 122 at apredetermined accuracy.

The adapter lens 301 is stored in the optical adapter 320. In addition,an adapter-side mount 331 serving as the concave side of the new commonstandard mount is provided at an end on the opposite side of the basestand-side mount 321 of the optical adapter 320. The adapter-side mount331 has a positioning reference hole 332 and is connected to the ΔCadapter 340. A base stand-side mount 341 that is the convex side of thenew common standard mount of the ΔC adapter 340 includes a positioningreference projection 358 which is fitted in the positioning referencehole 332 to connect the base stand-side mount 341 to the adapter-sidemount 331 of the optical adapter 320.

A camera-side mount 342 of the ΔC adapter 340 is a mount serving as theconcave side of the new common standard mount. The camera-side mount 342has a positioning reference hole 359 and is connected to the cameraadapter 360. On the other hand, in the camera adapter 360, anadapter-side mount 361 is the convex side of the new common standardmount and includes a reference projection 362 for positioning. Theadapter-side mount 361 of the camera adapter 360 is mounted on thecamera-side mount 342 of the ΔC adapter 340. When mounting the cameraadapter 360 on the ΔC adapter 340, the reference projection 362 of thecamera adapter 360 is fitted in the positioning reference hole 359 ofthe ΔC adapter 340, and the rotation direction of the camera adapter 360is uniquely determined with respect to the ΔC adapter 340. A camera lensmount 363 of the camera adapter 360 is a mount complying with a standardunique to the camera maker, and normally includes a positioningmechanism of a unique standard to a camera mount 402 of the digitalcamera 400.

With the above-described arrangement, via

-   -   mechanical connection between the eyepiece base 122 and the        optical adapter 320    -   mechanical connection between the optical adapter 320 and the ΔC        adapter 340    -   mechanical connection between the ΔC adapter 340 and the camera        adapter 360, and    -   mechanical connection between the camera adapter 360 and the        digital camera 400,

the positions of the eyepiece base 122 and the image sensor 401 of thedigital camera 400 in the rotation direction are defined within apredetermined accuracy. That is, the positional relationship in therotation direction between the X- and Y-axes of the microscope basestand 121 of the microscope and the X- and Y-axes of the image sensor401 of the digital camera 400 is ensured within the predeterminedaccuracy determined by the mechanical accuracy. In this case, since themechanical accuracies at the above-described four connection portionsare totaled, the rotation positioning accuracy is, for example, ±0.5 mm(about ±1°) at worst in the periphery with 50 mmΦ. This corresponds to arotational shift of ±0.5 mm at two ends of a 50 mm observation range.

The positioning accuracy by the above-described mechanical referencemechanism provided on the mount cannot implement the target accuracy of±0.1 μm, and cannot cope with the problem concerning the rotation of theimage sensor 401 described above with reference to FIG. 44. The ΔCadapter 340 according to this embodiment corrects the rotational shiftbetween the microscope base stand 121 and the image sensor 401 of thedigital camera 400, and implements the target accuracy of ±0.1 μm inaccurate position management. A vertical error of ±0.1 μm corresponds toabout ±0.1 millidegree at the two ends of a 56 mm observation range.Hence, the ΔC adapter 340 is required to have a capability of correctingan error within the range of about ±10 to about ±0.1 millidegree. Notethat practically, if the vertical error can be suppressed to ±0.1 μm(about ±3 millidegrees) at the two ends of a 2 mm observation range, alevel more than enough for pathological diagnosis is expected to beobtained. In this case as well, the ΔC adapter 340 needs to correct anerror within the range of about ±1° to about ±3 millidegree. Note that arange of ±2° to ±3° is sufficient as the maximum correction range of theΔC adapter 340. The ΔC adapter 340 includes a rotation mechanismconfigured to implement a function of performing alignment adjustment(rotation correction) at such an accuracy.

In FIG. 22, (22 a) shows the structure of the ΔC adapter 340. The mount341 is the convex side of the common standard mount including thepositioning reference projection 358 serving as a connection portion. Aninner cylinder portion 343 on the convex side is fixed to an outer ringportion 345 of a cross roller ring 344. An outer cylinder 346 isassembled to the upper portion of the outer ring portion 345. The outercylinder 346 includes an outer cylinder base plate 347. A ΔC drivingmotor 348, a ball screw 349 ((22 b) of FIG. 22), an electric circuitboard (not shown) for driving control, and the like are implemented onthe outer cylinder base plate 347. The mount 342 serving as the concaveside of the common standard mount is assembled to an inner ring portion350 of the cross roller ring 344. The inner ring portion 350 smoothlyrotates relative to the outer ring portion 345 via a roller bearing 351disposed between the outer ring portion 345 and the inner ring portion350 of the cross roller ring 344. That is, the mount 342 includes theconcave side of the common standard mount as the connection portion tothe camera adapter 360, and rotates relative to the base mount 341 thatis the convex side of the common standard mount. As a result, thedigital camera 400 rotates relative to the microscope base stand 121(eyepiece base 122). A driving mechanism that changes the arrangementrelationship (in this embodiment, the rotation positional relationship)between the mount 341 and the mount 342 is thus constituted.

In FIG. 22, (22 b) is a view showing the rotational driving method ofthe ΔC adapter 340. A screw shaft 352 of the ball screw 349 is formed atthe end of the rotor shaft of the ΔC driving motor 348 fixed on theouter cylinder base plate 347. Along with rotation of the screw shaft352, a nut portion 353 of the ball screw linearly moves in the axialdirection of the ΔC driving motor 348. At this time, a driving lineargear 354 fixed to the nut portion 353 of the ball screw also moves. Thecounterpart of fitting of the driving linear gear 354 is a driven arcgear 355 fixed to the outer wall of the mount 342 serving as the concaveside of the common standard mount. As the driving linear gear 354 moves,the mount 342 is rotationally driven. Rotation correction of the mount342 serving as the concave side of the common standard mount is thusperformed relative to the mount 341 serving as the convex side of thecommon standard mount. The ΔC driving motor 348 is driven by a controlcircuit (not shown) so as to rotate the mount 342 by a predeterminedangle in accordance with a driving instruction from the controller 501.Note that the rotational driving of the mount 342 can be done not onlyby the combination of a driving motor, a ball screw, and gears but alsoby, for example, ultrasonic driving using friction caused by a movingelement and a driving motor.

A ΔC initial position mark 356 used for initialization at the time ofactivation is attached to a predetermined position of the outer wall ofthe mount 342 serving as the convex side of the common standard mount,and defines the ΔC initial position. A ΔC initial position sensor 357 isdisposed on the outer cylinder base plate 347 so as to face the ΔCinitial position mark 356, and detects the initial position at the timeof activation. For example, when the ΔC initial position is assumed tobe the fitting position between a positioning reference hole and apositioning reference projection, the ΔC adapter 340 performs ΔCcorrection within the range of, for example, ±2° to ±3° based on thedetected initial position. That is, the ΔC adapter 340 according to thisembodiment performs coarse positioning (first adjustment) by themechanical positioning mechanisms using the positioning referenceprojections 322, 358, and 362 and the positioning reference holes 311,332, and 359 and the positioning mechanism by the ΔC initial positionsensor 357. After that, fine positioning (second adjustment) using theΔC driving motor 348 is done based on an image obtained by the imagesensor 401. By the two-stage positioning, the X- and Y-axis directionsof the image sensor 401 are accurately aligned with the X- and Y-axisdirections of the stage.

The slide (slide 700) with position references used in the microscopesystem 10 according to this embodiment will be described next. FIG. 23shows views for explaining the slide 700 according to this embodiment.As shown in (23 a) of FIG. 23, the slide 700 has the origin mark 701, aspare origin mark 702, a Y-axis mark 703, and focus reference marks 704,705, and 706. The origin mark 701 and the Y-axis mark 703 represent aspecific position on the Y-axis and a specific position on the X-axis,respectively, and at least one of the marks represents axis informationin the X direction or Y direction. With these marks, the slide referenceposition (origin position) and the axis direction can correctly bespecified. In this embodiment, the Y-axis mark 703 defines the Y-axisdirection. Position references with such a structure are suitable in acase in which only a strip-shaped narrow region is usable as the regionto arrange the marks. Both the origin mark 701 and the Y-axis mark 703are disposed in a vacant area between the label area 721 and the coverglass area 722 that is the arrangement position of a cover glass and aspecimen (tissue slice) as an observation object. Note that the specimenneeds to be placed within the range of the cover glass area 722.However, as for the cover glass, a cover glass larger than the coverglass area 722 may be used. At this time, it is all right to cover someor all of the focus reference marks 704 to 706 with the cover glass,although the focus position changes by only a distance uniquelydetermined by the refractive index and the thickness of the cover glass,as will be described later. That is, in this specification, the coverglass area 722 indicates the area in which the observation object isplaced but does not define the size of the cover glass. In addition, ifthe specimen arrangement position changes, and the blank area usable toarrange the position reference marks moves to the right end of the slide700 in the future, it is possible to cope with this change by disposingthe position reference marks according to this embodiment at the rightend.

In (23 a) of FIG. 23, the origin mark 701 is a position reference markof the slide 700, and serves as an origin used to manage the coordinatesof the observation position of a specimen on the slide 700. The spareorigin mark 702 is a spare origin used in a case in which the originmark 701 is undetectable because of dirt, a flaw, or the like. Theorigin mark 701 and the spare origin mark 702 are disposed in apredetermined positional relationship. The Y-axis mark 703 indicates aY-axis line having axis information in the Y direction. The axisdirection represented by the Y-axis mark 703 is a directionperpendicular to end faces in the longitudinal direction of the slide700. This direction will be referred to as a Y-axis direction. Theorigin mark 701, the Y-axis mark 703, and the spare origin mark 702 arearranged while being spaced apart from each other so they are notsimultaneously observed when observed at a magnification of themicroscope used to detect the center line (axis direction) (to bedescribed later). The origin mark 701 and the spare origin mark 702 arearranged on both sides of the Y-axis mark 703 on the center line of theY-axis mark 703. Note that although the center line of the Y-axis mark703 is used to specify the origin position, as will be described later,the present invention is not limited to this, and any line (to bereferred to as a reference line hereinafter) along the Y-axis directionuniquely defined by the Y-axis mark 703 is usable. A specific positionon the extension of the reference line is defined as the originposition. Hence, the origin mark 701 (or the spare origin mark 702) isarranged while being spaced apart from the Y-axis mark 703 so as toindicate a specific position on the extension of the reference line. Theorigin mark 701, the Y-axis mark 703, and the spare origin mark 702 willgenerically be referred to as position reference marks hereinafter.

These position reference marks are preferably disposed at intervalsequal to or more than the distance corresponding to the field size (forexample, the field size of a 10× objective lens=φ1.5 mm or more). Thisis because the adjacent position reference marks are prevented frombeing visually mixed in the same visual field of the microscope, and themarks can efficiently be detected. In addition, to obtain an accurateorigin reference, it is important to consider dirt or a flaw. Hence, ifdirt or a flaw is found by naked-eye detection or image recognition, ameasure to, for example, use the spare origin mark 702 in place of theorigin mark 701 is needed. Note that since the position of the spareorigin mark 702 with respect to the origin mark 701 is known, conversionof the coordinate values and the like can easily be done. The followingexplanation will be made assuming that the position reference marksconsidered not to be affected by dirt or a flaw are observed. To preventthe influence of dirt or a flaw, the position reference marks mayactively be covered using a somewhat large cover glass. Alternatively,position reference marks may be disposed at the left end of the lowersurface of the somewhat large cover glass, and the vacant area and theregion to place the specimen on the slide may be covered with the coverglass. In this case, the slide itself need not have the positionreference marks. Otherwise, position reference marks may be disposed onthe lower surface of the strip-shaped cover glass, and the strip-shapedcover glass with the position reference marks may be placed in thevacant area on the slide. In this case as well, the slide itself neednot have the position reference marks.

In FIG. 23, (23 b) and (23 c) show detailed examples of the positionreference marks. In (23 b) of FIG. 23, the origin mark 701 (or the spareorigin mark 702) uses two, upper and lower isosceles triangles, and thecontact point of their apexes is the origin (or the spare origin). TheY-axis mark 703 is formed from a complex of Y-axis lines havingdifferent widths, as shown in (23 b) of FIG. 23, and its center linerepresents the Y-axis of the origin. Note that the Y-axis mark 703 isdisposed to be perpendicular to the horizontal frames of the slide 700at a predetermined accuracy. The Y-axis lines having different widthsare arranged to cope with low to high magnifications of the objectivelens magnification.

The Y-axis mark 703 has the same pattern structure as the crosshatchY-axis 293. An example of the structure will be described with referenceto (12 a) and (12 b) of FIG. 12. The Y-axis mark 703 has a structure inwhich a plurality of pairs of lines with the same width are arranged tobe symmetric with respect to the center line serving as the axis ofsymmetry while changing the width. Note that as for the central portion,a certain line may exist on the center line. In addition, therelationship between lines and spaces may be reversed. Accordingly, inboth the angle of view at a low magnification of the objective lens andthe angle of view at a high magnification, an appropriate number oflines with appropriate widths are captured by imaging (in both liveimage and still image), and a predetermined accuracy is ensured inbarycentric detection (to be described later). The intervals of thecenter lines of the lines or spaces of the Y-axis mark, the boundaries(edges) between the lines and spaces, the widths of the lines or spaces,and the like are set to predetermined values and are useful as actualdistance information. Each of the Y-axis mark 703, the origin mark 701,and the spare origin mark 702 may be formed from an aggregate of pairsof fine lines and spaces having a width of, for example, 1 μm, like thecrosshatch Y-axis 293 or the crosshatch origin 291. This enablesinclusion of finer actual distance information. Note that the intervalsbetween the position reference marks on the slide 700, the sizes of thereference marks, the structures of the reference marks, the intervals ofthe center lines of the lines or spaces of the reference marks, theboundaries (edges) between the lines and spaces, the widths of the linesor spaces, and the like are set to predetermined values and are alsousable as actual distance information.

In FIG. 23, (23 c) shows another example of the origin mark 701 (or thespare origin mark 702) which is formed from a complex of X-axis lineshaving different widths, and its center line in the X-axis directionrepresents the X-axis of the origin or spare origin. Hence, theintersection between the center line in the X-axis direction obtainedfrom the origin mark 701 (or the spare origin mark 702) and the centerline in the Y-axis direction obtained from the Y-axis mark 703 is theorigin (spare origin) of the slide 700. Note that a more detailedstructure of the origin mark 701 (or the spare origin mark 702) shown in(23 c) of FIG. 23 is obtained by, for example, rotating (12 a) and (12b) of FIG. 12 by 90°.

As for the positional relationship between the position reference marks,the origin mark 701 and the spare origin mark 702 are arranged on thecenter line of the Y-axis mark 703, as shown in (23 b) and (23 c) ofFIG. 23. In this embodiment, the center line of each of the origin mark701 and the spare origin mark 702 is aligned with the center line of theY-axis mark. Additionally, like the dimensional relationship exemplifiedin (23 b) and (23 c) of FIG. 23, all of the sizes of the referencemarks, the distances between them, and the like are more than the fieldsize of a 10× objective lens, that is, φ1.5 mm.

The focus reference marks 704 to 706 are arranged on three sides (theupper side, the right side, and the lower side) of the cover glass area722. The focus reference marks 704 to 706 are used to measure focuspositions along the periphery of the cover glass area 722, thusobtaining the height distribution (to be also referred to as a ΔZdistribution hereinafter) of the surface of the slide 700, andreflecting it on the management of the observation position. This makesit possible to manage a variation in the Z-direction position of thesurface between slide glasses and perform more accurate positionmanagement in the Z direction. Note that to obtain the variation in theZ-direction position of the slide glass surface, focus positions aremeasured on the four sides of the cover glass area 722. For the leftside of the cover glass area 722, the Y-axis mark 703 is used. However,the present invention is not limited to this. As shown in (24 a) of FIG.24, a focus reference mark 707 may be provided on the left side of thecover glass area 722 as well, and focus positions based on the focusreference marks may be measured for the four sides of the cover glassarea 722.

In FIG. 24, (24 b) is a view showing details of the focus referencemark. In the focus reference mark according to this embodiment, focusreference unit marks (to be referred to as focus units hereinafter) 710each having a length of 2 mm are arranged at an even interval of, forexample, 1 mm. The focus reference mark is thus arranged in apredetermined width or less (in this example, 2 mm or less) from aposition spaced apart from a slide end by a predetermined distance (inthis example, 0.5 mm) to ensure a space to place an observation objectin the region surrounded by the focus reference marks. In addition, thefocus reference mark has a predetermined width or more to ensure aregion to cover the focus reference mark by the cover glass. The focusunit 710 is formed from a plurality of lines. For example, as shown inan enlarged view in (24 b) of FIG. 24, the focus unit 710 has astructure in which a plurality of pairs of lines with the same width arearranged to be symmetric with respect to the center line serving as theaxis of symmetry while changing the width. Note that a certain line mayexist on the center line. In addition, the relationship between linesand spaces may be reversed. Accordingly, in both the angle of view at alow magnification of the objective lens and the angle of view at a highmagnification, an appropriate number of lines with appropriate widthsare captured by the live image capturing function or the still imagecapturing function, and a predetermined accuracy is ensured in focusdetection (to be described later). The intervals of the center lines ofthe lines or spaces of the focus unit 710, the intervals of theboundaries (edges) between the lines and spaces, the widths of the linesor spaces, and the like are set to predetermined values and are usefulas actual distance information. Note that each line may further beformed from an aggregate of pairs of fine lines and spaces. The width ofthe fine line is set to, for example, 1/10 or less of the width of thenarrowest line (in this example, 10 μm) out of the plurality of linesthat form the mark (for example, 1 μm). This enables inclusion of fineractual distance information.

Note that these position reference marks or focus reference marks areintegrally formed by the same process to achieve the target accuracy andimplement cost reduction as expendables. For example, the positionreference marks or focus reference marks are formed on a slide at anaccuracy of 5 nm to 10 nm using a nanoimprint technology. For thisreason, the degree of alignment between the Y-direction center line ofthe Y-axis mark 703 and the Y-direction center lines of the origin marks701 and 702 and the perpendicularity between the Y-direction center line(origin Y-axis) of the Y-axis mark 703 and the X direction center lineof the origin mark 701 are formed on the nanometer order. Hence, theposition of the slide origin defined by the Y-axis mark 703 and theorigin mark 701 or the spare origin mark 702 and a slide X-axis 711 ((23b) and (23 c) of FIG. 23) and a slide Y-axis 712 ((23 b) and (23 c) ofFIG. 23) using the origin as the starting point have an accuracy on thenanometer order. Additionally, in this embodiment, the focus referencemarks 704 and 706 in the X direction along the long sides of the slide700 and the focus reference marks 705 and 707 in the Y direction alongthe short sides of the slide 700 are arranged such that the lines ofdifferent directions are arranged. However, lines of the same directionmay be arranged.

Note that the position reference marks or focus reference marks may beformed by another method such as printing, coloring, or etching on aglass surface. In this case, the position management accuracy and focusaccuracy lower. However, as compared to a case in which no referencesare formed at all, the same effect as in this embodiment can beobtained, though the degree of effect decreases. The pattern shape ofthe focus unit (focus reference unit mark) 710 of the focus referencemark can be any geometric shape as long as it can ensure the focusaccuracy. The repetitive pitch of the focus unit is not limited to 1 mmdescribed above. Focus units having a plurality of types of shapes maycoexist.

FIGS. 25 and 26 are block diagrams showing an example of the controlarrangement of the microscope system 10 according to this embodiment.The stage 200 is connected to the controller 501 via an interface cable13 such as a USB. In the stage 200, a stage MPU 280 controls return ofthe stage 200 to the origin position or movement of the stage 200according to an instruction from the controller 501. A ΔΘ drivingcircuit 281 drives the ΔΘ driving motor 611 of the ΔΘ stage 600 inaccordance with an instruction from the stage MPU 280. In accordancewith an instruction from the stage MPU 280, an X-axis driving circuit282 drives the X-axis driving motor 242 that moves the positionmanagement plane stage 220 in the X direction. In accordance with aninstruction from the stage MPU 280, a Y-axis driving circuit 283 drivesthe Y-axis driving motor 264 that moves the Y stage 240 in the Ydirection, thereby moving the position management plane stage 220 in theY direction.

An X-axis sensor processing circuit 284 generates an X-coordinate valuebased on a signal output from the X-axis sensor 271 upon detecting the Xarea scale 211, and supplies the X-coordinate value to the stage MPU280. A skew detecting sensor processing circuit 285 generates anX-coordinate value based on a signal output from the skew detectingsensor 273 upon detecting the X area scale 211, and supplies theX-coordinate value to the stage MPU 280. A Y-axis sensor processingcircuit 286 generates a Y-coordinate value based on a signal output fromthe Y-axis sensor 272 upon detecting the Y area scale 212, and suppliesthe Y-coordinate value to the stage MPU 280. Detection signals from theΔΘ initial position sensor 621, the X initial position sensor 243, andthe Y initial position sensor 265 are supplied to the stage MPU 280 andused for, for example, the initialization operations of the stages.

Note that the motor driving circuits such as the ΔΘ driving circuit 281,the X-axis driving circuit 282, and the Y-axis driving circuit 283, thestage MPU 280, the power supply circuit (not shown), and the likeconsume relatively high power and can be heat sources, and there is afear of the influence of thermal expansion on the position accuracy.Hence, these electric circuits may be stored in another housing asexternal controllers. In addition, the functions of the stage MPU 280may be implemented by the controller 501.

The microscope system 10 according to this embodiment includes the Zsensor 991 provided on the ΔZ base 901 of the ΔZ stage 900. Hence, asshown in FIG. 26, signals from the Z initial position sensor 991 a andthe Z-axis sensor 991 b of the Z sensor 991 are processed by a Z-axissensor processing circuit 1281 and input to the stage MPU 280. Inaddition, a ΔZ driving circuit 1282 configured to drive the ΔZ motor 913of the ΔZ lift unit 910 of the ΔZ stage 900 and process a signal fromthe ΔZ initial position sensor 920 a or the ΔZ-axis sensor 920 b isconnected to the stage MPU 280. Furthermore, a dZ driving circuit 1283configured to drive the dZ motor 653 of the dZ lift unit 650 of the ΔΘstage 600 and process a signal from the dZ initial position sensor 641 aor the dZ-axis sensor 641 b is connected to the stage MPU 280.

Referring back to FIG. 25, the ΔC adapter 340 of the adapter unit 300 isconnected to the controller 501 via an interface cable 12 such as a USB.In the ΔC adapter 340, a ΔC MPU 380 performs, for example, rotationcontrol of the mount 342 in the ΔC adapter 340 in accordance with aninstruction from the controller 501. A ΔC driving circuit 381 drives theΔC driving motor 348 in accordance with an instruction from the ΔC MPU380. A signal from the ΔC initial position sensor 357 is supplied to theΔC MPU 380 and used to return the mount 342 of the ΔC adapter 340 to theinitial position (the origin position of the rotation). Note that theelectric circuit components such as the ΔC driving circuit 381, the ΔCMPU 380, and the power supply circuit (not shown) consume relativelyhigh power and can be heat sources, and there is a fear of the influenceof thermal expansion on the position accuracy. Hence, these electriccomponents may be stored in another housing as external controllers. Inaddition, the functions of the ΔC MPU 380 may be implemented by thecontroller 501.

The digital camera 400 is connected to the controller 501 via theinterface cable 11 such as a USB, and transmits an image captured by theimage sensor 401 to the controller 501. In the digital camera 400, acamera MPU 480 executes each control of the digital camera 400. An imageprocessing circuit 481 processes an image signal obtained by the imagesensor 401 and generates digital image data.

Note that in this embodiment, a general-purpose digital camera is usedas the digital camera 400 and attached/detached via the adapter unit300. However, the present invention is not limited to this. For example,an imaging unit with the image sensor 401 may be fixed to the eyepiecebase 122. At this time, if the image sensor 401 is assembled in a statein which its X- and Y-axes accurately align with the X- and Y-axes ofthe stage, the rotation correction mechanism by the adapter unit 300 canbe omitted. Each of the above-described stage MPU 280, ΔC MPU 380, andcamera MPU 480 may implement various functions by executing apredetermined program or may be formed from a dedicated hardwarecircuit.

The controller 501 is a computer apparatus that includes, for example,the memory 512 that stores a program, and the CPU 511 that implementsvarious kinds of processing by executing the program stored in thememory 512, and has a measurement/control function in the microscopesystem 10. The operation of the microscope system 10 according to thisembodiment will be described below in detail.

FIG. 27 is a flowchart showing stage control by the controller 501 ofthe microscope system 10 according to this embodiment. Note that in themicroscope system 10 according to this embodiment, it is necessary todispose the Z scale 990 at a predetermined position of the microscopebase stand before an operation according to FIG. 27 is executed. Thedisposing method is as follows.

The Z base 130 is moved in the Z direction by the Z knob 125, and anin-focus position is searched for using, for example, the crosshatch290. The Z base 130 is lowered from the in-focus position in the minusdirection (downward) by, for example, 6 mm. The Z scale 990 is disposedsuch that the Z initial position sensor 991 a detects the Z initialposition mark 990 a at that position. Here, 6 mm is a value decided bythe maximum moving range of the ΔZ lift unit+the maximum moving range ofthe dZ lift unit+an error margin. As described above, the movable rangeof the lift pin of the ΔZ lift unit 910 is ±2 mm, and the movable rangeof the lift pin of the dZ lift unit 650 is ±0.2 mm. An operation rangedefined by these is 4.4 mm at maximum. When a margin is added inconsideration of an error at the time of disposition, the safe range is,for example, 6 mm. Note that at this stage, the dZ lift unit and the ΔZlift unit are in an uninitialized state before moving to initialpositions determined by the initial position marks. In theinitialization operation of the dZ lift unit 650 and the initializationoperation of the ΔZ lift unit 910 to be described below, the Z initialposition is set at a position at which the distal end of the objectivelens and the observation surface of the stage do not come into contactat any position in the movable range.

Referring back to FIG. 27, the operation of the controller 501 in themicroscope system 10 according to this embodiment will be described.When each unit of the microscope system 10 is powered on, and thecontroller 501 is instructed to execute an observation positionmanagement mode, the operation shown in the flowchart of FIG. 27 starts.

First, in step S11, the controller 501 initializes itself. In theinitialization of the controller 501, for example, configuration at thetime of activation is set on a platform used to execute a positionmanagement application having the measurement/control function in themicroscope system 10. When the configuration setting ends, for example,in Windows®, desired application software is automatically activatedfrom an activation shortcut placed in a startup folder. In thisembodiment, the activation shortcut of position management applicationsoftware (to be referred to as a position management applicationhereinafter) that implements the measurement/control function of themicroscope system is placed in the startup folder, and the positionmanagement application is automatically activated. When the positionmanagement application is activated in the above-described way, in stepS12, the controller 501 waits for a notification of completion of theinitialization operation to be described below.

FIG. 28 is a flowchart showing the initialization operation in themicroscope system 10. When the units are powered on, they perform theinitialization operations upon power-on as shown in FIG. 28 under thecontrol of the controller 501. First, in an initialization process P1shown in FIG. 28, the controller 501 moves the Z base 130 to theabove-described Z initial position. If the Z base 130 is located at theZ initial position, the distal end of the objective lens mounted in themicroscope body and the observation surface of the stage do not comeinto contact at any position in the movable range in the subsequentinitialization operation. Note that if the moving operation of the Zbase 130 of the microscope is a manual operation, the controller 501prompts the user to do the operation via a predetermined UI, and theuser manually operates the Z knob 125. When electrically performing theoperation, the controller 501 controls the movement of the Z base 130.When the Z initial position sensor 991 a of the Z sensor 991 disposed onthe ΔZ base 901 of the ΔZ stage 900 detects the Z initial position mark990 a of the Z scale 990 (step S131), the controller 501 sets a readvalue Z of the Z-coordinate to zero (step S132). Accordingly, in thesubsequent initialization operation, the distal end of the objectivelens mounted in the microscope body and the observation surface of thestage do not come into contact at any position in the movable range.

When the initialization process P1 is completed, in an initializationprocess P2, the controller 501 performs the initialization operations ofthe stage 200, the adapter unit 300 (ΔC adapter 340), the digital camera400, and the ΔZ stage 900 (including the Z base 130).

Initialization of XY Stage (Stage 200)

In step S101, the stage MPU 280 of the stage 200 moves the positionmanagement plane stage 220 and the Y stage 240 to the initial positions(the X initial position mark 234 and the Y initial position mark 253),respectively, thereby initializing the XY stage. That is, the stage MPU280 sends a driving control command for a predetermined direction toeach of the X-axis driving circuit 282 and the Y-axis driving circuit283. For example, a moving direction and a moving speed are added to thedriving control command as parameters. Upon receiving the drivingcontrol commands, the X-axis driving circuit 282 and the Y-axis drivingcircuit 283 respectively send driving signals to the X-axis drivingmotor 242 and the Y-axis driving motor 264 and move the X stage(position management plane stage 220) and the Y stage 240 in accordancewith the designated directions and speeds.

The stage 200 includes the X-axis sensor processing circuit 284 and theY-axis sensor processing circuit 286 which perform interpolationprocessing of detection signals from the X-axis sensor 271 and theY-axis sensor 272 capable of accurately detecting the X area scale 211and the Y area scale 212, respectively. In this interpolationprocessing, if, for example, a 1/2000 interpolation operation isperformed, a resolution of 10 nm or less is obtained from a 2 μm wideline pattern, and the target position management accuracy of theobservation position management microscope system according to theembodiment, that is, an accuracy of 0.1 μm can be obtained. The stageMPU 280 accurately grasps and manages the X-direction moving amount andposition (X-coordinate) of the position management plane stage 220 andthe Y-direction moving amount and position (Y-coordinate) of the Y stage240 based on the signals from the X-axis sensor processing circuit 284and the Y-axis sensor processing circuit 286.

When the X initial position mark 234 on the position management planestage 220 reaches the detection position of the X initial positionsensor 243, a status change from the X initial position sensor 243 istransmitted to the stage MPU 280. Similarly, when the Y initial positionmark 253 on the Y stage 240 reaches the detection position of the Yinitial position sensor 265, a status change from the Y initial positionsensor 265 is transmitted to the stage MPU 280. Upon receiving thestatus changes, the stage MPU 280 sends a stop control command to eachof the X-axis driving circuit 282 and the Y-axis driving circuit 283 andstops the XY driving of the stage 200.

Next, the stage MPU 280 sends a control command to each of the X-axisdriving circuit 282 and the Y-axis driving circuit 283 to sequentiallyperform forward and reverse fine movements by setting a lower movingspeed, selects a more correct initial position, and stops the positionmanagement plane stage 220 and the Y stage 240. Then, the stage MPU 280resets the X-coordinate value and the Y-coordinate value obtained basedon the signals from the X-axis sensor processing circuit 284 and theY-axis sensor processing circuit 286 and held in itself to zero, andsets the XY initial position of the XY stage (coordinates (0, 0)). Notethat the detection accuracy of the XY initialization position by the Xinitial position mark, the Y initial position mark, the X initialposition sensor, and the Y initial position sensor includes a smallreproducibility error (a slight shift occurs when re-initialization isperformed) caused by the mechanical accuracy. However, the moving amountof the stage is accurately managed by the area scales and thepredetermined detection units (the X-axis sensor 271, the Y-axis sensor272, and the skew detecting sensor 273). In this embodiment, the Xinitial position mark and the Y initial position mark are disposed basedon the crosshatch origin 291, thereby making the XY initial positioncorrespond to the crosshatch origin 291 at a predetermined accuracy(predetermined mechanical error range).

Initialization of ΔΘ Stage 600

Next, in step S102, the stage MPU 280 sends a driving control commandfor a predetermined direction to the ΔΘ driving circuit 281. Forexample, a moving direction and a moving speed are added to the drivingcontrol command as parameters. Upon receiving the driving controlcommand, the ΔΘ driving circuit 281 sends a driving signal to the ΔΘdriving motor 611, thereby rotating the rotary stage 691 of the ΔΘ stage600 in accordance with the designated direction and speed. When the ΔΘinitial position mark 620 reaches the detection position of the ΔΘinitial position sensor 621, a status change from the ΔΘ initialposition sensor is transmitted to the stage MPU 280. Upon receiving thestatus changes, the stage MPU 280 sends a stop control command to the ΔΘdriving circuit 281 and stops the ΔΘ driving. Next, the stage MPU 280issues a control command to the ΔΘ driving circuit 281 to sequentiallyperform forward and reverse fine rotations by setting a lower movingspeed, selects a more correct initial position, and stops the ΔΘ stage600. Then, the stage MPU 280 resets the ΔΘ-coordinate value held initself to zero, and obtains a ΔΘ center position, that is, a correctposition without a rotational shift. If the ΔΘ position of the ΔΘ stage600 at the time of activation is unknown (for example, in a case inwhich the position is not saved in the nonvolatile memory), for example,the ΔΘ stage 600 is rotated by 3° in one direction, and if the ΔΘinitial position mark 620 cannot be found, returned by 6° in the reversedirection.

Initialization of dZ Lift Units 650

In step S103, the stage MPU 280 sends a control command to the dZdriving circuit 1283, drives each dZ motor 653 of the ΔΘ stage 600, andinitializes the Z-direction position of each dZ lift unit 650 of the ΔΘstage 600. The dZ motor 653 is stopped at a position at which the dZinitial position based on the dZ initial position mark 640 a of the dZscale 640 is detected by the dZ initial position sensor 641 a, therebyreturning the dZ lift pin to the initial position. In step S104, in thisstate, the stage MPU 280 initializes the read values (dZ1, dZ2, and dZ3)of the dZ linear scales 640 b by the dZ-axis sensors 641 b to zero. Theabove-described initialization processing is executed independently foreach of the three dZ lift units 650. Note that as for the read values bythe dZ-axis sensors 641 b, as shown in (14 c) of FIG. 14, the read valueat the upper left point (left on the microscope base stand side) is dZ1,the read value at the upper right point (right on the microscope basestand side) is dZ2, and the read value on the lower side (opposite sideof the microscope base stand) is dZ3.

When initialization of the XY stage of the stage 200, the ΔΘ stage 600,and the dZ lift units 650 is completed in the above-described way, thestage MPU 280 transmits a stage initialization end command to thecontroller 501 in step S105.

Initialization of ΔC Adapter 340

The initialization operation of the ΔC adapter 340 (the second adapterunit in the adapter unit 300) will be described next. In step S111, theΔC MPU 380 sends a driving control command for a predetermined directionto the ΔC driving circuit 381. For example, a moving direction and amoving speed are added to the driving control command as parameters.Upon receiving the driving control command, the ΔC driving circuit 381sends a driving signal to the ΔC driving motor 348. When the ΔC drivingmotor 348 is driven, the mount 342 serving as the concave side of thecommon standard mount of the ΔC adapter 340 rotates in accordance withthe designated direction and speed. When the ΔC initial position mark356 on the mount 342 serving as the concave side of the common standardmount reaches the detection position of the ΔC initial position sensor357, a status change is transmitted from the ΔC initial position sensor357 to the ΔC MPU 380. Upon receiving the status changes, the ΔC MPU 380sends a stop control command to the ΔC driving circuit 381 and stops theΔC driving motor 348.

Next, the ΔC MPU 380 issues a control command to the ΔC driving circuit381 to sequentially perform forward and reverse fine rotations bysetting a lower moving speed, selects a more correct initial position,and stops the rotational driving. Then, the ΔC MPU 380 resets theΔC-coordinate value (the rotation angle of the ΔC adapter) held initself to zero, and obtains a ΔC center position, that is, a correctposition without a rotational shift. Note that if the ΔC position at thetime of activation is unknown (for example, in a case in which theposition is not saved in the nonvolatile memory), for example, the ΔCadapter is rotated by 3° in one direction, and if the ΔC initialposition mark cannot be found, returned by 6° in the reverse direction.When the ΔC adapter 340 is set at the initial rotation position in theabove-described way, the ΔC MPU 380 transmits a ΔC adapterinitialization end command to the controller 501 in step S112.

Note that absolute-type scales and sensors may be used to manage theposition of the XY stage in the stage 200, the rotation position of theΔΘ stage 600, the dZ position, and the rotation position of the ΔCadapter 340. When absolute-type scales and sensors are used, theabove-described detection of the XY initial position of the stage 200and detection of the initial positions of the ΔΘ stage 600 and the ΔCadapter 340 and the initial positions of dZ1, dZ2, and dZ3 can beomitted.

Initialization of Digital Camera 400

The camera MPU 480 of the digital camera 400 performs configurationsetting for the operation of a predetermined position managementcorresponding function (to be described later) (step S121). When theinitialization ends, a camera initialization end command is transmittedto the controller 501 (step S122). Note that in this embodiment, thedigital camera 400 executes camera operation initialization when poweredon, and transmits a completion notification to the controller 501.However, the present invention is not limited to this. For example, thecontroller 501 may instruct initialization (step S121) to set theconfiguration to make a predetermined position management correspondingfunction (to be described later) from the user interface of the digitalcamera 400.

Initialization of ΔZ Stage 900

In step S133, the ΔZ lift units 910 are driven via the ΔZ drivingcircuit 1282 to move the ΔZ stage 900 to the ΔZ initial position. In astate in which the initial position of the Z base 130 is detected in theinitialization process P1, the stage 200 and the objective lens unit 126are sufficiently spaced apart. Hence, the initialization of the ΔZ stage900 can safely be executed.

Step S133 will be described in detail. The stage MPU 280 sends a controlcommand to the ΔZ driving circuit 1282, drives each ΔZ motor 913 of theΔZ lift units 910, and moves each lift pin 914 in the Z direction. TheΔZ motor 913 is stopped at a position at which the initial positionbased on the ΔZ initial position mark 994 a of the ΔZ scale 994 isdetected by the ΔZ initial position sensor 920 a, thereby completingreturn of the lift pin 914 to the initial position. In step S134, thestage MPU 280 sets read values ΔZ1, ΔZ2, and ΔZ3 of the ΔZ linear scale994 b by the ΔZ-axis sensor 920 b to zero. Note that as for the readvalues by the ΔZ-axis sensor 920 b, as shown in (5 e) of FIG. 5, theread value at the upper left point (L1) is ΔZ1, the read value at theupper right point (L2) is ΔZ2, and the read value on the lower side (L3)is ΔZ3 when viewed from the upper surface side of the ΔZ stage 900. Theabove-described initialization processing is executed independently foreach of the three ΔZ lift units 910. Note that absolute-type scales andsensors may be used to manage the ΔZ position. When absolute-type scalesand sensors are used, the above-described detection of the initialpositions of ΔZ1, ΔZ2, and ΔZ3 can be omitted. After that, in step S135,the stage MPU 280 sends a ΔZ initialization end command to thecontroller 501.

When the above-described initialization process P2 ends, the controller501 advances to an initialization process P3. In step S136 of theinitialization process P3, the controller 501 moves the positionmanagement plane stage 220 in the Z direction, and determines whetherthe XY crosshatch 213 is at the focus position of the digital camera400. That is, the controller 501 prompts the user to do an operation,and the user manually operates the Z knob 125, thereby adjusting theZ-direction position of the position management plane stage 220 andperforming focusing. As described above concerning step S131, if the Zbase 130 can be driven in the Z direction by a motor or the like, thecontroller 501 may drive the motor incorporated in the microscope bodyto perform automatic focusing. Note that if the Z-axis of the microscopeis driven by a motor, that is, electrically driven, a predetermined Zdriving interface (not shown) is provided, and the controller 501controls via the Z driving interface. The controller 501 determines thefocus state from a captured image obtained by capturing the XYcrosshatch 213 by the digital camera 400 and notifies the stage MPU 280of it. When a focus is detected, the stage MPU 280 stores the read valueZ of the Z linear scale 990 b by the Z-axis sensor 991 b in the memory,and simultaneously, notifies the controller 501 of it. Note that in theXY crosshatch 213 used to detect a focus, any one of the crosshatch 290,the crosshatch origin 291, the crosshatch X-axis 292, and the crosshatchY-axis 293 is usable.

Referring back to FIG. 27, after the controller 501 ends theinitialization of itself (step S11), as described above, and theinitialization process P1, the initialization process P2, and theinitialization process P3 end, the process advances from step S12 tostep S13, and the position management application starts a preparationoperation for observation position management.

In step S13, the controller 501 drives the ΔZ stage 900 (ΔZ lift units910) to correct the slant (tilt) of the surface of the stage 200(position management plane stage 220) with respect to the optical axis.In this tilt correction, the XY plane of the stage 200 is adjusted suchthat it becomes parallel to a vertical plane of the Z-axis that is thedirection of observation light. This tilt correction processing will bedescribed with reference to the flowchart of FIG. 29. Note that in theflowchart of FIG. 29, if the controller 501 drives the stage 200 and theΔZ stage 900, the processing is implemented by, for example, giving aninstruction from the controller 501 to the stage MPU 280.

First, the controller 501 moves the position management plane stage 220such that the center of the observation position is located at the leftend of the crosshatch X-axis 292 (step S151). Next, the controller 501synchronously drives the ΔZ lift pins 914 (to be discriminately referredto as the ΔZ lift pins L1 to L3 hereinafter, as shown in FIG. 5) of thethree ΔZ lift units 910 to attain a focus on the crosshatch X-axis 292(step S152). Note that synchronous driving of the three ΔZ lift pins L1to L3 is control to simultaneously move all the ΔZ lift pins L1 to L3from their ΔZ initial positions by the same amount in the Z direction.The controller 501 stores, in the memory, scale values (ΔZ1 to ΔZ3)obtained when a focus is attained at the left end of the crosshatchX-axis 292 (step S153). The scale values ΔZ1 to ΔZ3 are scale valuesthat use the ΔZ initial position marks obtained by the ΔZ-axis sensors920 b provided on the ΔZ lift units of the ΔZ lift pins L1 to L3 as areference (zero). Note that since ΔZ1 to ΔZ3 are the same value, onlyone of them needs to be stored. In this embodiment, ΔZ1 is used. Thisvalue will be referred to as ΔZc1 hereinafter.

Next, the controller 501 moves the position management plane stage 220such that the center of the observation position is located at the rightend of the crosshatch X-axis (step S154). The controller 501synchronously drives the ΔZ lift pins L1 to L3 of the three ΔZ liftunits 910 to attain a focus on the crosshatch X-axis 292 (step S155).The controller 501 stores, in the memory, a scale value (one of ΔZ1 toΔZ3, in this embodiment, ΔZ1 is used) obtained when a focus is attainedat the right end of the crosshatch X-axis 292 as ΔZc2 (step S156). Then,the controller 501 moves the position management plane stage 220 suchthat the center of the observation position is located at the lower endof the crosshatch Y-axis 293 (step S157). The controller 501synchronously drives the ΔZ lift pins L1 to L3 to attain a focus on thecrosshatch Y-axis 293 (step S158). The controller 501 stores, in thememory, a scale value (one of ΔZ1 to ΔZ3, in this embodiment, ΔZ1 isused) obtained when a focus is attained by synchronous driving of the ΔZlift pins L1 to L3 as ΔZc3 (step S159).

The controller 501 estimates the variation amount (the tilt amount inthe X direction) between the ΔZ lift pin L1 and the ΔZ lift pin L2 fromthe difference between ΔZc1 and ΔZc2, and moves the ΔZ lift pin L2 suchthat the variation amount becomes zero (step S160). For example, assumethat the distance between the ΔZ lift pin L1 and the ΔZ lift pin L2 isRh, and the distance between the left and right ends of the crosshatchX-axis (the moving amount of the center of the observation position instep S154) is λh, as shown in (5 e) of FIG. 5. In this case, thevariation amount (ΔZ2−ΔZ1) between the ΔZ lift pin L1 and the ΔZ liftpin L2 is estimated asΔZ2−ΔZ1=(ΔZc2−ΔZc1)*Rh/λh

The controller 501 moves the ΔZ lift pin L2 by the estimated variationamount to eliminate the tilt of the stage 200 in the X direction.

Next, the controller 501 estimates the variation amount (the tilt amountin the Y direction) between the ΔZ lift pin L1 and the ΔZ lift pin L3from the difference between ΔZc1 and ΔZc3, and moves the ΔZ lift pin L3such that the variation amount becomes zero (step S161). For example,assume that the distance between the ΔZ lift pin L1 and the ΔZ lift pinL3 is Ri, and the moving distance to the lower end of the crosshatchY-axis (the moving amount of the center of the observation position instep S157) is λi, as shown in (5 e) of FIG. 5. In this case, thevariation amount (ΔZ3−ΔZ1) between the ΔZ lift pin L1 and the ΔZ liftpin L3 is estimated asΔZ3−ΔZ1=(ΔZc3−ΔZc1)*Ri/λi

The controller 501 moves the ΔZ lift pin L3 by the estimated variationamount to eliminate the tilt of the stage 200 in the Y direction.

With the above-described processing, correction of the tilt of theposition management plane stage 220 is implemented. From then on, whendriving the ΔZ stage, the ΔZ lift pins L1 to L3 are synchronously drivento do positioning in the Z direction to maintain the state in which thetilt of the stage 200 is corrected. As for the position management inthe Z direction (Z-coordinate), the sum of the read value Z of the Zlinear scale 990 b and one (in this embodiment. ΔZ1) of the read valuesΔZ1 to ΔZ3 of the ΔZ linear scale 994 b corresponding to the ΔZ liftpins L1 to L3 is used. In this embodiment, Z+ΔZ1 (+dZ (zero at thisstage)) is used. That is, the Z-coordinate of the XY crosshatch 213 isZ+ΔZ1 (+dZ (zero at this stage)). Note that the value Z is the movingamount from the Z initial position (zero), and the value ΔZ1 is themoving amount from the ΔZ1 initial position (zero). Since the tilt ofthe position management plane stage 220 is corrected by the aboveprocessing, the position of the surface of the position management planestage 220 in the optical axis direction (Z direction) is correctlymanaged. Note that after that, the Z knob 125 is not operated, and themovement in the Z direction is performed only by driving the ΔZ liftunits using the ΔZ knob 904 or by a ΔZ lift unit driving instructionfrom the controller 501. The ΔZ knob 904 is, for example, an electricknob using a rotary encoder. The ΔZ lift pins L1 to L3 are synchronouslydriven in accordance with a change of the value of the rotary encoder bya knob operation. Note that the above-described tilt correctionprocessing (steps S151 to S161) may be repeated until the variationamounts estimated in steps S160 and S161 decrease to a predeterminedvalue or less.

Note that in the above-described correction of the slant (tilt) of thesurface of the stage 200 (position management plane stage 220) withrespect to the optical axis, position reference marks that provides theX- and Y-axis references are used as the focus references. That is, theleft and right ends of the crosshatch X-axis 292 and the lower end ofthe crosshatch Y-axis 293 are used as the focus references. However, themarks that provide the focus references are not limited to this form,and any mark that is provided in the observable region of the digitalcamera 400 for performing imaging and allows the digital camera 400 toperform focus detection is usable. More specifically, a mark thatprovides a focus reference is provided on the XY plane in theobservation field at a position difference from the slide placementposition.

For example, as shown in (52 a) of FIG. 52, the XY crosshatch 213including a dedicated focus reference mark 294 may be used. As shown in(52 a) of FIG. 52, the focus reference mark 294 is a rectangle formedfrom, for example, two parallel sides each having a predetermined widthalong the X-axis direction and two parallel sides each having apredetermined width along the Y-axis direction. The focus reference mark294 is provided on the same plane as the XY plane of the crosshatchX-axis 292 and the crosshatch Y-axis 293. The rectangle has apredetermined rectangular size capable of representing the slant of theslide placement surface on the XY stage. In this case, the XYtwo-dimensional scale plate 210 is disposed such that the rectangularplane formed by the focus reference mark 294 on the XY stage becomesparallel to the slide placement surface of the XY stage. In addition,the focus reference mark 294 is disposed, for example, between thecrosshatch 290 and the crosshatch X-axis 292 and the crosshatch Y-axis293 at a predetermined interval (2 mm, as shown in (52 b) of FIG. 52).That is, to efficiently detect the mark positions, the reference marksare disposed at intervals equal to or more than a distance equivalent tothe field size (in this embodiment, equal to or more than the field size(1.5 mm) of the 10× objective lens) so as not to simultaneously observeadjacent position reference marks within the same visual field of themicroscope. The focus reference mark 294 serves as a focus referencecapable of representing the slant of the slide placement surface on theXY stage, like the crosshatch X-axis 292 and the crosshatch Y-axis.

In FIG. 52, (52 b) is a view showing details of the focus referencemark. A focus reference mark 295 in the X-axis direction is formed fromfocus reference unit marks (to be referred to as focus unitshereinafter) 297 in the Y-axis direction having a length of 2 mm eachand arranged at an interval of, for example, 1 mm. The focus unit 297has a structure in which a plurality of pairs of lines with the samewidth are arranged to be symmetric with respect to the center lineserving as the axis of symmetry while changing the width. Note that acertain line may exist on the center line. In addition, the relationshipbetween lines and spaces may be reversed. Accordingly, in both the angleof view at a low magnification of the objective lens and the angle ofview at a high magnification, an appropriate number of lines withappropriate widths are captured by the live image capturing function orthe still image capturing function, and a predetermined accuracy isensured in focusing (to be described later). A focus reference mark 296in the Y-axis direction is formed from focus reference unit marks (to bereferred to as focus units hereinafter) 298 in the X-axis directionhaving a length of 2 mm each and arranged at an interval of, forexample, 1 mm. The focus unit 298 has a pattern obtained by rotating thefocus unit 297 by 90°. Each of the focus units 297 and 298 is formedfrom a plurality of lines of different line widths.

When the dedicated focus reference mark 294 is used, steps S151, S154,and S157 in the above-described correction of the slant (tilt) of thesurface of the stage 200 (position management plane stage 220) withrespect to the optical axis (FIG. 29) can be performed using, forexample, the focus units 297 at two points on the focus reference mark295 in the X-axis direction on the upper side and the focus unit 297 atone point on the focus reference mark 295 in the X-axis direction on thelower side shown in (52 c) of FIG. 52. Hence, the necessary focus unitsare three focus units, that is, two focus units spaced apart at apredetermined distance along the X-axis direction and one focus unitlocated at a position spaced apart from the side formed by the two focusunits at a predetermined distance in the Y-axis direction. Note that thetriangle formed by the three focus units used to correct the tilt ispreferably similar to the triangle formed by the three lift pins 914. Inthe above embodiment, two focus units are arranged in the X-axisdirection. However, two focus units may be arranged in the Y-axisdirection. That is, focus positions are measured at the apex positionsof a triangle having one side aligned with the X-axis direction orY-axis direction in both a case in which the focus units 297 and 298 areemployed and a case in which the crosshatch X-axis 292 and thecrosshatch Y-axis 293 are used.

The correction of the slant (tilt) of the surface of the stage 200(position management plane stage 220) with respect to the optical axismay be performed using a slide with focus references (FIGS. 23 and 24)in which the specifications (flatness and parallism) of the slidesurface are managed within a predetermined accuracy. In this case, λjand λk are used as the values λh and λi used to estimate the variationamounts ((14 c) of FIG. 14).

Referring back to FIG. 27, in step S14, the controller 501 controls theΔC adapter 340 so as to align the X- and Y-axes of the image sensor 401with the X- and Y-axes of the stage based on the image of the XYcrosshatch 213 on the stage 200 captured by the digital camera 400. ΔCcorrection for aligning the array of the pixels of the image sensor 401with the stage X-axis 203 and the stage Y-axis 204 of the stage 200 isthus performed.

FIG. 30 is a flowchart for explaining the ΔC correction operation. Asdescribed above, the purpose of ΔC correction is to align the X- andY-axes of the pixel array of the image sensor 401 with the X- and Y-axesof the stage 200. In this embodiment, axis alignment between the X- andY-axes of the image sensor 401 and the X- and Y-axes of the XYcrosshatch 213 disposed in the observation object region 205 andrepresenting the X- and Y-axes of the stage 200 is performed.

First, in step S201, the controller 501 in which the position managementapplication is operating sends a predetermined control command to thecamera MPU 480 to set the digital camera 400 in a color live mode. Inthe color live mode, the camera MPU 480 of the digital camera 400captures a color low-resolution still image (a thinned image capturedwithout using all pixels of the image sensor) of an observed image, andtransmits it to the controller 501 at a predetermined time interval asneeded. Every time the low-resolution still image is transmitted fromthe digital camera 400, the controller 501 displays it on the display502, thereby providing a live image.

In step S202, using, for example, the display 502, the controller 501prompts the observer (the operator or the user) to change the objectivelens of the microscope to a low magnification (for example, 10×). Afterchanging the objective lens to the 10× objective lens by rotating therevolver 127, the observer notifies the controller 501 via an input unit(for example, a keyboard operation or a mouse operation on a GUI) (notshown) that the 10× objective lens is being used. Note that if themicroscope includes a motor-driven revolver, the low magnificationsetting of the objective lens may automatically be executed by sending apredetermined control command from the controller 501 to the microscope.

In step S203, the controller 501 sends a control command to the stageMPU 280 to move the observation position onto the crosshatch X-axis 292of the XY crosshatch 213 arranged so as to be captured by the digitalcamera 400. Note that the observation position (coordinates) of thecrosshatch X-axis 292 has known coordinate values based on the stageorigin. The crosshatch X-axis 292 is spaced apart from other positionreference marks at distances equal to or more than, for example, thefield size (for example, φ1.5 mm) of the 10× objective lens so as not tobe visually mixed with the other marks. For this reason, the live imageof only the crosshatch X-axis 292 is displayed on the display 502. In(31 a) of FIG. 31, reference numeral 801 denotes an imaging field by theimage sensor 401. Note that as shown in (31 b) of FIG. 31, the imagingfield 801 of the image sensor 401 is inscribed in a region 804 that isnarrower than an observation field 803 of the microscope (opticalsystem) and is located in the observation field 803 and also has a moreuniform light amount and less distortion. However, for safety's sake, aregion 802 smaller than the imaging field 801 may be set as the imagingfield of the image sensor 401. Note that the field size of theobservation field 803 of the image sensor 401 is adjusted by themagnification of the adapter lens 301 in the optical adapter 320.

In steps S204 to S207, the angle of view for imaging by the digitalcamera 400 is adjusted. For example, first, in step S204, the controller501 calculates the Y-direction barycentric position (the barycenter ofthe pixel values) of the black image of the crosshatch X-axis 292 in theimaging field 801. Note that in this embodiment, the Y-directionbarycentric position of the black image is obtained. However, thepresent invention is not limited to this, and the Y-directionbarycentric position of the white image may be obtained. Alternatively,the average value of the Y-direction barycentric position of the blackimage and that of the white image may be used. In step S205, thecontroller 501 sends a control command to the stage MPU 280 to move theXY stage such that the barycenter calculated in step S204 is located atthe center of the imaging field. In step S206, the controller 501determines whether the angle of view of imaging by the image sensor 401meets a condition. In this embodiment, based on the number of linesand/or the size of the line width of the black or white image of thecrosshatch X-axis 292 in the imaging field 801 assumed for, for example,a 40× objective lens, the controller 501 determines whether the angle ofview meets the condition. Upon determining that the angle of view meetsthe condition, the process advances from step S206 to step S208. If theangle of view does not meet the condition, the process advances fromstep S206 to step S207. In step S207, using, for example, the display502, the controller 501 prompts the observer (operator or user) toincrease the magnification of the objective lens of the microscope. In acase of a motor-driven revolver, the high magnification setting of theobjective lens is automatically done by sending a control command fromthe controller 501 to the microscope.

By repeating steps S204 to S207 described above, the objective lens isswitched from the low magnification (10×) to the high magnification bythe manual operation of the user or the control command, and the stagemoves to the barycentric position calculated in step S204. In thisembodiment, an angle of view as shown in (31 c) of FIG. 31 is finallyobtained by the 40× objective lens. Note that the magnification of theobjective lens may be changed stepwise from 10×→20×→40× or changed in astroke from 10×→40×.

Upon determining in step S206 that the angle of view meets thecondition, the angle of view is considered to have changed to the angleof view corresponding to the 40× objective lens, and the processadvances to step S208. In step S208, the controller 501 sends a controlcommand to the camera MPU 480 to switch the digital camera 400 to ameasurement mode. The measurement mode is a mode to use the imageinformation of the image sensor 401 on a pixel basis. For example, ifthe image sensor 401 uses color filters in a primary color Bayerarrangement for color image capturing as shown in (31 e) of FIG. 31, theimage processing circuit 481 handles the image of each of RGB pixels asa monochrome signal. At this time, the image processing circuit 481normalizes the image signals from the RGB pixels and adjusts theirdynamic ranges. Nonlinear processing such as gamma processing is notperformed, and the image signals from the pixels which remain linear arcprocessed and output. The measurement mode is the position managementcorresponding function including image processing such as accuratebarycenter calculation and implemented in the digital camera 400.

Note that instead of using the above-described measurement mode, animage obtained in an existing color mode or monochrome mode (a luminancesignal calculated from RGB signals is used) may be used. In this case,however, the accuracy of the calculation result of barycentercalculation or the like lowers. Alternatively, a monochrome camerawithout color filters may be used. However, color observation isimpossible when observing a slide.

Next, in steps S209 to S212. ΔC correction is executed. First, in stepS209, the controller 501 sends a control signal to the camera MPU 480 todo still image capturing using all pixels of the image sensor 401 in themeasurement mode. A partially enlarged view of the thus obtained stillimage of the crosshatch X-axis 292 is shown on the right side of (31 c)of FIG. 31. The image of the crosshatch X-axis captured by the pixels ofthe image sensor 401 is obtained as a moire image that reflects theaxial shift between the image sensor and the crosshatch X-axis. That is,in the measurement mode, since information is obtained on a pixel basis,an accurate calculation result (centroidal line to be described later)can be obtained.

In step S210, the controller 501 measures the slant (axial shift), thatis, calculates the rotational shift angle between the crosshatch X-axis292 and the X-axis of the image sensor 401. As the calculation method,as shown in (31 d) of FIG. 31, the imaging field of the image sensor 401is divided into strip-shaped partial regions in the X-axis direction bystrip regions 810 having the same width, and the barycenter iscalculated for each strip region (partial region). The narrower thewidth of the strip region is, the higher the detection accuracy is.Hence, a width corresponding to one pixel may be set. That is, a stripregion whose width is equal to or more than one pixel can be used. Toprevent the influence of a pixel defect of the image sensor 401, a stripregion having a width corresponding to a plurality of pixels may be setand shifted by the width of one pixel to subdivide the visual field. Anangle α of the rotational shift is accurately obtained from the changeamount of the Y-coordinate value of the barycenter of each strip region.For example, a centroidal line 811 passing through a plurality ofbarycentric positions obtained from a plurality of strip regions iscalculated by the least-squares method or the like, and the rotationalshift angle α is obtained from the angle difference between thecentroidal line 811 and the X direction of the array of pixels of theimage sensor 401.

In step S211, it is determined whether the slant amount (rotationalshift angle) measured in step S210 falls within a tolerance (equal to orless than a predetermined threshold). If the slant does not fall withinthe tolerance, in step S212, the controller 501 sends a control commandto the ΔC MPU 380 to rotate the mount 342 (that is, the image sensor401) of the ΔC adapter 340 in a predetermined direction by apredetermined angle. As described above concerning the ΔC adapter 340,the predetermined threshold is preferably 3 millidegrees, and morepreferably 0.1 millidegree. In the ΔC adapter 340, the ΔC driving motor348 is driven in accordance with the control command to rotate the mount342 by a predetermined angle. The predetermined angle is an angle equalto or less than the predetermined threshold (preferably 3 millidegreesor less, and more preferably 0.1 millidegree or less). After that, theprocess returns to step S209 to capture a still image (step S209) andmeasure the slant (step S210). The controller 501 repeats theabove-described processes (steps S209 to S212). Upon determining in stepS211 that the slant amount falls within the tolerance, the processadvances to step S213. In step S213, the controller 501 sends a controlsignal to the camera MPU 480 to return the digital camera 400 to thecolor live mode, and ends the ΔC correction.

Note that in step S212, the mount 342 of the ΔC adapter 340 is rotatedby a predetermined amount. However, the present invention is not limitedto this. For example, if the arrangement can control the rotation amountof the mount 342 by the ΔC driving motor 348, control may be done so asto rotate the mount 342 by an amount corresponding to the slant (theangle difference α corresponding to the rotational shift) calculated instep S210. The crosshatch X-axis 292 is used as a pattern arranged to becaptured by the digital camera 400. However, the present invention isnot limited to this, and for example, the crosshatch Y-axis 293 or thecrosshatch 290 may be used. Part of the X area scale 211 or the Y areascale 212 may be arranged to be captured by the digital camera 400 andused. As adjustment (change) of the arrangement of the image sensor 401with respect to the microscope body 100, rotation adjustment (ΔCcorrection) is performed above. However, the present invention is notlimited to this. For example, a function of performing fine adjustmentin the Z direction may be provided in addition to the function of ΔCcorrection by the ΔC adapter 340 or as the fourth adapter. For example,the adapter unit 300 may be allowed to adjust the Z-direction positionof the image sensor 401 and perform fine focus adjustment. In this case,for example, the ΔC adapter 340 can use a structure that supports threepoints by three actuators to be driven in the Z direction. The slant ofthe imaging plane of the image sensor 401 with respect to the XY planemay be adjusted. This can be done by detecting a change in the focus ofthe grating pattern (a change in the blur of the grating pattern) in thecaptured image of the crosshatch 290 and thus determining the slant ofthe imaging plane. The slant of the imaging plane can be adjusted byadjusting the driving amounts of the above-described three actuators.The ΔC correction is implemented by the adapter unit 300 above. However,the stage 200 may be provided with a rotation mechanism for ΔCcorrection.

When the ΔC correction is completed in the above-described way, theprocess advances to step S15 of FIG. 27. In step S15, the controller 501accurately detects the crosshatch origin 291 (serving as one of thereference values of a position management accuracy of 0.1 μm), and setsthe X- and Y-coordinate values and the Z coordinate value (Z+ΔZ+dZ) ofthe crosshatch origin as the stage origin. The accurate detection of thecrosshatch origin is implemented using, for example, the crosshatchX-axis 292 and the crosshatch origin 291. FIG. 32 is a flowchart forexplaining the processing of stage origin detection (detecting thecrosshatch origin and setting the X- and Y-coordinate values and the Zcoordinate value of the crosshatch origin as the stage origin). FIG. 33shows views of examples of images captured by the digital camera 400 inthe stage origin detection processing. The stage origin detectionprocessing will be described below with reference to FIGS. 32 and 33.

First, in step S241, the controller 501 moves the center of theobservation position to the crosshatch X-axis 292 such that the lines ofthe crosshatch X-axis 292 enter the imaging field 801 of the digitalcamera 400, as shown in the left view of (33 a) of FIG. 33. At thistime, focusing is performed by synchronous driving of the lift pins L1to L3. The focusing can be done either by manually operating the ΔZ knob904 or by automatic control based on focus information obtained from theimage captured by the digital camera 400. In step S242, the controller501 captures a still image of the crosshatch X-axis 292, divides thestill image into the strip regions 810, obtains a centroidal line 812 ofthe crosshatch X-axis 292 from barycenter calculation based on the stripregions, and obtains the Y-coordinate value. The controller 501 sends acontrol command to the stage MPU 280 to move the stage in the Ydirection such that the calculated centroidal line aligns with a centerline 813 of the imaging field 801 of the image sensor 401 in the X-axisdirection using the Y-coordinate value (step S243). The center line ofthe imaging field 801 of the image sensor 401 in the X direction is thusaligned with the center line of the crosshatch X-axis 292 in the Xdirection, as shown in the right view of (33 a) of FIG. 33. TheY-coordinate of the stage origin is determined in this state. Hence, instep S244, the controller 501 sets the read value of the Y area scale212 by the Y-axis sensor 272 to the Y-coordinate value of the stageorigin.

Next, in step S245, the controller 501 sends a control command to thestage MPU 280 to move the observation position to the crosshatch origin291. At this time, focusing is performed by synchronous driving of theΔZ lift pins L1 to L3. The focusing can be done either by manuallyoperating the ΔZ knob 904 or by automatic control based on focusinformation obtained from the image captured by the digital camera 400.Note that since the focusing is performed in step S241, and an excellentfocus is still attained even after the observation position is moved tothe crosshatch origin 291, the focusing in step S245 may be omitted.When the position management plane stage 220 is moved by a predeterminedamount rightward in the X direction up to the X initial position (the Xvalue is zero), the crosshatch origin 291 is captured within the imagingfield 801 of the image sensor 401, as shown in the upper view of (33 b)of FIG. 33. However, the position after the movement of the stageincludes a mechanical error of the disposing position of the X initialposition mark (an error that occurs when the X initial position mark ismechanically disposed in accordance with the X-direction position of thecrosshatch origin 291). For this reason, the centroidal line of thecrosshatch origin 291 in the Y direction has a slight shift from thecenter line of the imaging field 801 of the image sensor 401 in the Ydirection.

Hence, in step S246, the controller 501 captures a still image of thecrosshatch origin 291, and obtains a centroidal line 814 of thecrosshatch origin 291 in the Y direction from barycenter calculationbased on the strip regions. In step S247, the controller 501 sends acontrol command to the stage MPU 280 to move the stage in the Xdirection such that the obtained centroidal line 814 aligns with acenter line 815 of the imaging field 801 of the image sensor 401 in theY direction. The centroidal line of the crosshatch origin 291 in the Ydirection can thus be aligned with the center line of the imaging field801 of the image sensor 401 in the Y direction, as shown in the lowerview of (33 b) of FIG. 33. The X-coordinate of the crosshatch origin 291is determined in this state. Hence, in step S248, the controller 501stores the read value of the X area scale 211 by the X-axis sensor 271in the memory as the X-coordinate value of the stage origin. Note thatthe crosshatch Y-axis 293 may be used in place of the crosshatch origin291. In this case, after the stage is moved by a predetermined amount inthe Y direction, the centroidal line in the Y direction is obtained bythe same processing as the above-described contents, and aligned withthe center line of the imaging field 801 of the image sensor 401 in theY direction, thereby determining the X-coordinate of the crosshatchorigin 291. The X-coordinate value is stored as the stage origin in thememory. In the above-described way, the coordinates are obtained in thestate in which the center of the imaging field 801 aligns with thecrosshatch origin 291, and set as the stage origin (X, Y). In step S249,the controller 501 obtains the read value Z+ΔZ1+dZ1 (dZ1 is zero at thisstage) in the state in which the focus is attained in step S245, andstores it in the memory as the Z-coordinate value of the stage origin.In step S250, the controller 501 sends a control command to the cameraMPU 480 to switch the digital camera 400 from the measurement mode tothe color live mode.

Referring back to FIG. 27, when the stage origin detection is completedin the above-described way, the controller 501 notifies the observer ofa slide loading permission using the display 502, and waits forplacement of the slide on the ΔΘ stage 600 (step S16). Note that slideplacement (the presence/absence of slide loading) can be detected eitherby automatic detection (not shown) or based on a manual instruction.When the slide is placed on the ΔΘ stage 600, the controller 501determines whether an origin mark and a focus reference mark exist onthe placed slide (step S17). If an origin mark and a focus referencemark exist on the placed slide, the process advances to step S18. Notethat since the stage origin is obtained, a position where a positionreference mark (to be referred to as an origin mark hereinafter) existsand a position where a focus reference mark exists on the loaded slidecan be grasped accurately to some extent. Hence, the presence/absence ofthe origin mark or position reference mark can be determined by movingthe stage to the position where the mark should be observed anddetermining whether the mark exists there.

In step S18, the controller 501 corrects the tilt of the slide surfaceusing the focus reference marks 704 to 706 and the Y-axis mark 703 (orfocus reference mark 707) of the slide 700. The slide tilt correctionprocessing will be described below in detail with reference to theflowchart of FIG. 34.

In step S261, the controller 501 moves the position management planestage 220 such that the center of the observation position is located atthe upper end of the Y-axis mark 703, the origin mark 701, the upper endof the focus reference mark 707 on the left side, or the left end of thefocus reference mark 704 on the upper side. In step S262, the controller501 performs focusing using the above-described focus units on the slide700 by synchronously driving the dZ lift pins 654 of the three dZ liftunits 650 from their initial positions. The three dZ lift pins 654 willdiscriminately be referred to as the dZ lift pins 654 M1 to M3hereinafter, as shown in (14 c) of FIG. 14. Note that the scale valuesdZ1 to dZ3 are scale values that use the dZ initial position marks 640 aobtained by the dZ-axis sensors 641 b near the dZ lift units having thedZ lift pins M1 to M3 as a reference (zero). In step S263, thecontroller 501 stores the scale values (dZ1 to dZ3) obtained when afocus is attained in the memory as dZc1. Note that since dZ1 to dZ3 arethe same value, only one of them needs to be stored, and in thisembodiment, the value dZ1 is used.

Next, in step S264, the controller 501 moves the position managementplane stage 220 in the X direction such that the center of theobservation position is located at the upper end of the focus referencemark 705 on the right side or the right end of the focus reference mark704 on the upper side. In step S265, the controller 501 performsfocusing on the above-described focus units on the slide 700 bysynchronously driving the dZ lift pins M1 to M3. In step S266, thecontroller 501 stores the scale values (dZ1 to dZ3) obtained when afocus is attained in the memory as dZc2 (since dZ1 to dZ3 are the samevalue, only one of them needs to be stored, and in this embodiment, thevalue dZ1 is used). Then, in step S267, the controller 501 moves theposition management plane stage 220 in the Y direction such that thecenter of the observation position is located at the center of the focusreference mark 706 on the lower side. In step S268, the controller 501performs focusing on the marks on the slide 700 by synchronously drivingthe dZ lift pins M1 to M3. In step S269, the controller 501 stores thescale values (dZ1 to dZ3) obtained when a focus is attained in thememory as dZc3 (since dZ1 to dZ3 are the same value, only one of themneeds to be stored, and in this embodiment, the value dZ1 is used).

In step S270, the controller 501 estimates the variation amount (thetilt amount of the slide in the X direction) between the dZ lift pin M1and the dZ lift pin M2 from the difference between dZc1 and dZc2, andmoves the dZ lift pin M2 such that the variation amount becomes zero.For example, assume that the distance between the dZ lift pin M1 and thedZ lift pin M2 is Rj, and the distance between the left and right endsof the mark on the slide 700 (the moving amount of the center of theobservation position in step S264) is λj, as shown in (14 c) of FIG. 14.In this case, the variation amount (dZ2−dZ1) between the dZ lift pin M1and the dZ lift pin M2 is estimated asdZ2−dZ1=(dZc2−dZc1)*Rj/λj

The controller 501 moves the dZ lift pin M2 by the estimated variationamount to eliminate the tilt of the slide 700 in the X direction.

In step S271, the controller 501 estimates the variation amount (thetilt amount in the Y direction) between the dZ lift pin M1 and the dZlift pin M3 from the difference between dZc1 and dZc3, and moves the dZlift pin M3 such that the variation amount becomes zero. For example,assume that the distance between the dZ lift pin M1 and the dZ lift pinM3 is Rk, and the moving distance to the lower end of the mark on theslide 700 (the moving amount of the center of the observation positionin the Y direction in step S267) is λk, as shown in (14 c) of FIG. 14.In this case, the variation amount (dZ3−dZ1) between the dZ lift pin M1and the dZ lift pin M3 is estimated asdZ3−dZ=(dZc3−dZc1)*Rk/λkThe controller 501 moves the dZ lift pin M3 by the estimated variationamount to eliminate the tilt of the slide 700 in the Y direction.

With the above-described processing, the tilt of the upper surface ofthe slide 700 placed on the ΔΘ stage 600 with respect to the opticalaxis is corrected. From then on, the controller 501 manages theZ-coordinate of the upper surface of the slide by Z+ΔZ1+dZ1. Note thatthe value Z is the moving amount from the Z initial position (zero), thevalue ΔZ1 is the moving amount from the ΔZ1 initial position (zero), andthe value dZ1 is the moving amount from the dZ1 initial position (zero).With the above processing, the tilt of the slide surface is corrected inaddition to the tilt of the position management plane stage 220, and theZ position of the slide surface in the optical axis direction (Zdirection) is correctly managed. After that, the Z-direction movement isperformed by synchronous driving of the ΔZ lift pins L1 to L3. With theabove processing, the tilt derived from the slide surface is eliminated,and more accurate position management in the Z direction is implemented.Note that the above-described tilt correction processing (steps S261 toS271) may be repeated until the variation amounts estimated in stepsS270 and S271 decrease to a predetermined value or less.

Referring back to FIG. 27, the controller 501 executes ΔΘ correction ofthe ΔΘ stage 600 to correct the rotational shift of the placed slide(step S19). As described above, ΔC correction is executed before ΔΘcorrection, and the X-axis direction and the Y-axis direction of thestage 200 align with those of the image sensor 401. By the ΔΘcorrection, the X-axis direction and the Y-axis direction of theposition reference mark on the slide 700 are aligned with those of theimage sensor 401. As a result, the X-axis direction and the Y-axisdirection of the stage 200 and those of the position reference on theslide 700 are aligned with each other via the image sensor 401. The ΔΘcorrection operation will be described below with reference to FIG. 35.

FIG. 35 is a flowchart for explaining the ΔΘ correction operationaccording to the embodiment. In step S301, the controller 501 sets theobjective lens to a low magnification (for example, 10×) by a manualoperation or by sending a control command to the microscope. In stepS302, the controller 501 sends a control command to the stage MPU 280 tomove the observation position onto the Y-axis mark 703 (FIGS. 23 and 24)on the slide placed on the ΔΘ stage 600. Note that the position(coordinates) of the Y-axis mark 703 on the slide 700 includes an errorcaused by the rotational shift based on the placed state of the slide.However, when the observation position is moved using known coordinatevalues of the Y-axis mark 703 from the stage origin, the mark can becaptured within the visual field of, for example, the 10× objectivelens. The Y-axis mark 703 is spaced apart from other position referencemarks at distances equal to or more than, for example, the field size(for example, φ1.5 mm) of the 10× objective lens so as not to bevisually mixed with the other marks, as described above with referenceto FIGS. 23 and 24. Hence, as shown in (36 a) of FIG. 36, only theY-axis mark 703 exists in the imaging field 801 of the image sensor 401,and the live image of only the Y-axis mark 703 is displayed on thedisplay 502.

In step S303, the controller 501 calculates the barycentric position ofthe black image of the Y-axis mark 703 in the imaging field 801. Notethat in this embodiment, the X-direction barycentric position of theblack image is obtained. However, the present invention is not limitedto this, and the X-direction barycentric position of the white image maybe obtained. Alternatively, the average value of the X-directionbarycentric position of the black image and that of the white image maybe used. In step S304, the controller 501 sends a control command to thestage MPU 280 to move the stage 200 such that the barycentric positionis located at the center of the visual field. In step S305, thecontroller 501 determines the angle of view based on the number of linesand/or the size of the width of the black or white image of the Y-axisline mark in the imaging field 801 assumed for, for example, a 40×objective lens. If the angle of view does not meet a condition, theprocess advances from step S305 to step S306. Using, for example, thedisplay 502, the controller 501 prompts the observer (operator or user)to increase the magnification of the objective lens of the microscope.In a case of a motor-driven revolver, the high magnification setting ofthe objective lens may automatically be done by sending a controlcommand from the controller 501 to the microscope.

By repeating steps S303 to S306 described above, the objective lens isswitched from the low magnification (10×) to the high magnification bythe manual operation of the user or the control command, and in stepS304, the stage moves to the barycentric position calculated in stepS303. In this embodiment, an angle of view as shown in (36 b) of FIG. 36is finally obtained by the 40× objective lens. Note that themagnification of the objective lens may be changed stepwise from10×→20×→40× or changed in a stroke from 10×→40×. Upon determining instep S305 that the angle of view for the 40× objective lens is obtained,the process advances to step S307.

In step S307, the controller 501 sends a control command to the cameraMPU 480 to switch the digital camera 400 to a measurement mode, as instep S208. Next, in step S308, the controller 501 sends a control signalto the camera MPU 480 to do still image capturing using all pixels ofthe image sensor 401 in the measurement mode. A partially enlarged viewof the thus obtained still image of the Y-axis mark 703 is shown on theright side of (36 b) of FIG. 36. The image of the Y-axis line capturedby the pixels of the image sensor 401 is obtained as a moire image thatreflects the axial shift between the image sensor and the Y-axis line.

In step S309, the controller 501 measures the slant (axial shift), thatis, calculates the rotational shift angle between the Y-axis of theimage sensor 401 and the Y-axis mark 703 on the slide 700. As thecalculation method, for example, as shown in (36 c) of FIG. 36, theimaging field of the image sensor 401 is divided in the Y-axis directionby strip regions having the same width, and the barycenter is calculatedfor each strip region. The narrower the width of the strip region is,the higher the detection accuracy is. Hence, a width corresponding toone pixel may be set. To prevent the influence of a pixel defect of theimage sensor, a strip region having a width corresponding to a pluralityof pixels may be set, and the region is shifted by the width of onepixel to subdivide the visual field. The rotational shift angle isaccurately obtained from the change amount of the X-coordinate value ofthe barycenter of each strip region. For example, a centroidal line 822passing through a plurality of barycentric positions obtained from aplurality of strip regions is calculated by the least-squares method orthe like, and an angle β of the rotational shift between the centroidalline 822 and the Y direction of the array of pixels of the image sensor401 is obtained.

In step S310, the controller 501 determines whether the slant anglemeasured in step S309 falls within a tolerance (equal to or less than apredetermined threshold). If the slant angle does not fall within thetolerance, the process advances to step S311, and the controller 501sends a control command to the stage MPU 280 to rotate the ΔΘ stage 600in a predetermined direction by a predetermined amount. As describedabove concerning the ΔΘ stage 600, the predetermined threshold ispreferably 3 millidegrees, and more preferably 0.1 millidegree. In theΔΘ stage 600, the ΔΘ driving motor 611 is driven in accordance with thecontrol command to rotate the ΔΘ stage 600 by a predetermined amount(predetermined angle). The predetermined angle is an angle equal to orless than the above-described predetermined threshold (preferably 3millidegrees or less, and more preferably 0.1 millidegree or less).Then, the process returns to step S308, and the controller 501 performsstill image capturing and slant measurement in the measurement mode(step S309). If the slant falls within the tolerance, the ΔΘ correctionends.

Note that in step S311, the ΔΘ stage 600 is rotated by a predeterminedamount. However, the present invention is not limited to this. Forexample, if the arrangement can control the rotation amount of the ΔΘstage 600 (slide) by the ΔΘ driving motor 611, control may be done so asto rotate the ΔΘ stage 600 by an amount corresponding to the slant(rotational shift angle β) calculated in step S309.

Referring back to FIG. 27, when the ΔΘ correction is completed in theabove-described way, in step S20, the controller 501 starts detectingthe slide origin of the slide placed on the ΔΘ stage 600. The detectedslide origin is used as a reference position to manage the observationposition (coordinates) on the slide 700 using the position (coordinates)of the stage 200. That is, the difference between the coordinate valuesof the slide origin measured as the position of the stage 200 based onthe stage origin and the coordinate values of the stage at theobservation position based on the stage origin is calculated, therebyobtaining coordinate values depending on the slide origin (independentof the stage origin). The coordinate values are used as the coordinatesof the observation position. In other words, the observation position(coordinates) on the slide 700 is managed based on the stage originusing the difference between the coordinate values of the slide originbased on the stage origin and the coordinate values of the observationposition based on the stage origin. The coordinates of the observationposition on the slide thus become the position (coordinates) of thestage 200 based on the slide origin serving as the reference position.Note that at the time of execution of step S20, the objective lens isset to 40×, and the digital camera 400 is set in the measurement mode(in steps S305, S306, and S307). FIG. 37 is a flowchart of the slideorigin detection operation according to the embodiment.

The controller 501 captures a still image of the Y-axis mark 703 afterΔΘ correction in step S401, and obtains a centroidal line by barycentercalculation using strip regions in step S402. Note that as a precaution,focusing may be performed before the still image capturing. In stepS403, the controller 501 sends a control command to the stage MPU 280 tomove the stage in the X direction such that the calculated centroidalline aligns with the center line of the imaging field of the imagesensor 401 in the Y-axis direction. In this way, a center line 842 ofthe imaging field 801 of the image sensor 401 in the Y direction isaligned with a center line 841 of the Y-axis mark 703 in the Ydirection, as shown in (38 a) of FIG. 38.

In step S404, the controller 501 sends a control command to the stageMPU 280 to receive stage coordinate values at this time based on thestage origin obtained in step S15. Note that stage coordinates areobtained by replacing X- and Y-coordinates based on the XY initialposition with those based on the crosshatch origin 291, and the originis the stage origin. The stage origin of the stage coordinates hascoordinates (0, 0). The X-coordinate value of the coordinate values isthe X-coordinate value (defined as x0) of the center line of theaccurate slide origin in the Y direction. The X-coordinate value alsoserves as the X-coordinate value of the center line 842 of the imagingfield 801 of the image sensor 401 in the Y direction.

In step S405, the controller 501 sends a control command to the stageMPU 280 to move the image sensor observation position onto the originmark 701 of the slide 700. At this time, focusing is executed bysynchronous driving of the ΔZ lift pins L1 to L3. The focusing can beeither a manual operation or an automatic operation based on focusinformation. The axial shift of the slide Y-axis 712 ((23 b) and (23 c)of FIG. 23) is eliminated by ΔΘ correction. For this reason, when thestage is moved upward in the Y direction by a predetermined amount, theorigin mark 701 appears within the imaging field 801 of the image sensor401, as shown in (38 b) of FIG. 38. However, the stage moving positionincludes a positional shift error in the Y-axis direction that remainsafter the ΔΘ correction of the rotational shift of the slide (the totalerror is about 0.1 to 0.2 mm). For this reason, a centroidal line 851 ofthe origin mark in the X direction has a slight shift from a center line852 of the imaging field 801 of the image sensor 401 in the X direction.

The controller 501 captures a still image of the origin mark 701 in thestate shown in (38 b) of FIG. 38 in the measurement mode in step S406,and obtains the barycentric position in the Y direction by barycentercalculation using strip regions in step S407. In step S408, thecontroller 501 sends a control command to the stage MPU 280 to move thestage in the Y direction such that the obtained centroidal line 851aligns with the center line 852 of the imaging field 801 of the imagesensor 401 in the X direction. In this way, the centroidal line 851 ofthe origin mark 701 in the X direction can be aligned with the centerline 852 of the imaging field 801 of the image sensor 401 in the Xdirection, as shown in (38 c) of FIG. 38. Note that (38 b) and (38 c) ofFIG. 38 show a case in which the origin mark shown in (23 b) of FIG. 23is used, and (38 d) and (38 e) of FIG. 38 show a case in which theorigin mark shown in (23 c) of FIG. 23 is used.

In step S409, the controller 501 sends a control command to the stageMPU 280 to receive stage coordinate values at this time based on thestage origin (coordinates (0, 0)) obtained in step S15. The Y-coordinatevalue of the coordinate values is the Y-coordinate value (defined as y0)of the center line of the accurate slide origin in the X direction. TheY-coordinate value also serves as the Y-coordinate value of the centerline of the observation field of the image sensor 401 in the Xdirection.

In step S410, the controller 501 sends a control command to the stageMPU 280 to receive the Z-coordinate value (Z+ΔZ1+dZ1) obtained in stepS405. The received Z-coordinate value is the coordinate value (definedas a slide Z origin z0) of the accurate slide origin in the Z direction.Note that at this time, the degree of focusing may be confirmed again asa precaution. If the numerical value ΔZ1 has a slight change as theresult of reconfirmation, Z+ΔZ1+dZ1 with the numerical value is thecoordinate value (slide Z origin z0) of the slide origin in the Zdirection.

In step S411, the controller 501 changes the reference of positionmanagement of the observation position from the stage origin (the X- andY-coordinates are (0, 0), and the Z coordinate is Z+ΔZ1+dZ1) obtained instep S15 to the slide origin (x0, y0, z0) obtained in step S405. In stepS412, the controller 501 sends a control command to the camera MPU 480to switch the digital camera 400 from the measurement mode to the colorlive mode. Note that the slide origin detection of step S20 ispreferably executed every time the objective lens (magnification) ischanged. This is because the optical axis may shift upon switching theobjective lens. This will be described later.

Referring back to FIG. 27, in step S21, the controller 501 measures theδZ distribution of the slide surface of the slide 700 placed on the ΔΘstage 600. The measurement processing of the δZ distribution of theslide surface will be described with reference to the flowchart of FIG.39. First, in step S441, the controller 501 moves the observationposition to the position of the slide origin detected in step S20. Instep S442, the controller 501 performs focusing based on the imagecaptured by the digital camera 400 by driving the ΔZ lift units 910 andthus synchronously driving the ΔZ lift pins L1 to L3. In step S443, thecontroller 501 reads the scale value ΔZ1 in the in-focus state and setsZ+ΔZ1+dZ1 to the slide Z origin z0. Note that if the slide Z originobtained by the slide origin detection processing described withreference to FIG. 37 is used, the processes of steps S441 to S443described above can be omitted.

In step S444, the controller 501 moves the observation position to afocus unit or position reference mark to measure the focus positionfirst on four sides, that is, the focus reference marks (in thisembodiment, the set of focus units 710 at an interval of, for example, 1mm) 704 to 706 and the Y-axis mark 703 or the focus reference mark 707.In step S445, the controller 501 performs focusing based on the imagecaptured by the digital camera 400 by driving the ΔZ lift units 910 andthus synchronously driving the ΔZ lift pins L1 to L3. In step S446, thecontroller 501 reads the difference δZ between the scale value ΔZ1 inthe in-focus state and the scale value ΔZ1 at the slide Z origin, andstores the X- and Y-coordinates of the current observation position andthe read difference (δZ) of the Z-coordinate. In the processes of stepsS444 to S446 described above, measurement is repetitively executed forthe focus units 710 at an interval of, for example, 1 mm on each side.When the measurement of δZ is ended for all the positions ofpredetermined focus units 710, the process advances from step S447 tostep S448. In step S448, the controller 501 estimates the distribution(to be referred to as a δZ distribution hereinafter) of Z-coordinateswith respect to the slide Z origin on the slide surface (cover glassarea 722) by linear interpolation of δZ of the focus units at fourpoints of the focus reference marks (including the position referencemarks) on the four sides (the upper side, the lower side, the left side,and the right side).

For example, as shown in (50 a) and (50 b) of FIG. 50, δZ is estimatedfrom the values δZ (left δZx, right δZx, upper δZy, and lower δZy) at atotal of four points, that is, two points along the X-axis and twopoints along the Y-axis. For example, the controller 501 performs anX-direction interpolation operation of left δZx and right δZx and anY-direction interpolation operation of upper δZy and lower δZy, andcalculates the average of the two interpolated values, therebyestimating δZ. The δZ distribution on arbitrary lattice points at apitch of, for example, 1 mm (the disposing pitch of the focus units) onthe slide surface in the cover glass area 722 can thus be obtained. Inaddition, for example, as shown in (51 a) and (51 b) of FIG. 51, whensimilar interpolation processing is performed for arbitrary positions inthe lattice of a pitch of 1 mm, the δZ distribution at arbitrarypositions (x, y) on the slide surface in the cover glass area 722 can beobtained. This is expressed as δZ=δZ(x, y). Note that in theabove-described example, the δZ distribution is obtained by linearinterpolation. This is because the change of the slide surface ismoderate, and a sufficient accuracy is obtained. Multidimensionalinterpolation or any other arithmetic processing may be performed, as amatter of course.

Using the above-described δZ distribution, when the observation positionis moved to an arbitrary position (x, y) on the slide surface, δZ(x, y)is reflected on the Z-coordinate, thereby maintaining the height of theobservation position from the slide surface almost constant. Forexample, when the XY stage is moved from (x1, y1) to (x2, y2), the ΔZstage is controlled to move the Z-coordinate by δZ(x2, y2)−δZ(x1, y1),thereby maintaining the height of the observation position from theslide surface more uniform.

Note that in the measurement of the focus units arranged at an intervalof 1 mm in the focus reference mark on each side, the presence/absenceof the cover glass has an influence. If a cover glass exists, the focallength changes to be long. That is, the refractive index of the coverglass for the microscope is about 1.53. However, since the thicknessvaries within the range of 0.12 to 0.17 mm, the change amount alsovaries from 42 μm (when the thickness is 0.12 mm) to 60 μm (when thethickness is 0.17 mm). This is reflected on the value δZ. Hence, thesize of the cover glass in use affects the measurement of the δZ planedistribution. Cover glass sizes have a plurality of types. For example,heights are 24 mm and 25 mm, and lengths are 32 mm to 60 mm. There arefollowing cases depending on the positional relationship between thecover glass size and the focus reference on the slide 700.

(1) The height of the cover glass is 25 mm, and the length is 55 mm to60 mm

(2) The height of the cover glass is 25 mm, and the length is 50 mm

(3) The height of the cover glass is 25 mm, and the length is 45 mm to32 mm

(4) The height of the cover glass is 24 mm

Note that the size of the cover glass is selected in accordance with thesize of the specimen to be placed. Additionally, the cover glass isgenerally aligned with the right end of the slide glass.

In (1), all of the position reference marks (701 to 703) and the threefocus reference marks (704 to 706) or four focus reference marks (704 to707) of the slide 700 are covered with the cover glass, and theabove-described δZ distribution measurement method is applied.

In (2), only the position reference marks on the slide 700 are locatedoutside the cover glass, and the three or four focus reference marks arecovered with the cover glass. In this case, since the cover glass doesnot exist on the position reference marks, the focus position movesclose to the objective lens side by 42 to 60 μm. Hence, the focusposition varies between the position reference marks and the focusreference marks 704 to 707 covered with the cover glass because of thepresence/absence of the cover glass. The position reference marks cannotbe used in focusing. Since the tilt of the slide is about 20 μm, achange in δZ more than that can be recognized by the controller 501 asthe difference caused by the presence/absence of the cover glass. Hence,in this case, if the focus reference mark 707 on the left side coveredwith the cover glass is detected, this is selected, and theabove-described δZ distribution measurement method is applied. On theother hand, if the focus reference mark 707 does not exist, the focusreference marks (704 and 706) disposed on the upper and lower sides ofthe slide 700 are used, and the δZ distribution is obtained byperforming interpolation processing based on the measurement result ofthe upper and lower focus positions.

In (3), the left side of each of the focus reference marks (704 and 706)disposed on the upper and lower sides of the slide 700 falls outside thecover range of the cover glass. The range outside the cover glass can bedetected based on the change amount of δZ, as described above. Hence, inthe range with the cover glass, interpolation processing is performedbased on δZ of the upper and lower focus reference marks (704 and 706).

In (4), since the height of the cover glass is 24 mm, the upper andlower focus reference marks partially fall outside the cover range ofthe cover glass. Even if the cover glass is placed along the upper sideof the slide glass, the focus reference mark on the lower side iscovered 0.5 mm in width with the cover glass. Hence, when measuring δZof the upper and lower focus reference marks, the stage is moved in theX and Y directions within the width (2 mm originally) of the focusreference mark covered with the cover glass. The range where the coverglass exists is specified based on the change amount of the value δZ,and δZ within that range is used. The same δZ distribution measurementprocessing as in the cases (1) to (3) can thus be applied in accordancewith the size of the cover glass in the longitudinal direction.

Note that if the height of the specimen is large, and the placementrange needs to be ensured up to the positions of the upper and lowerfocus reference marks, a slide that does not have the upper and lowerfocus reference marks may be used. However, even in this case, when thelength of the cover glass is 50 mm or more, the left and right focusreferences are covered with the cover glass, and interpolationprocessing can be performed based on δZ of the left and right focusreferences.

In (1), since the position reference marks are also covered with thecover glass, the value at an arbitrary position (x, y) of the δZdistribution indicates the Z-direction position from the Z-coordinate ofthe slide origin. Hence, the δZ distribution represents theZ-coordinates of the slide surface. On the other hand, in (2) to (4),the position reference marks are located outside the cover glass. Hence,the δZ distribution represents a relative variation of the slide surfacebut does not indicate the Z-direction position of the slide surfaceitself. As shown in (49 c) of FIG. 49, a focal length L2 increases dueto the cover glass. Letting L1 be the focal length at a position withoutthe cover glass, and ΔL be the change amount of the focal lengthgenerated by the cover glass, L2=L1+ΔL holds. The change amount ΔL basedon the presence/absence of the cover glass can be obtained by measuringfocus positions in a portion where the cover glass exists and a nearbyportion where the cover glass does not exist for the focus referencemarks or the position reference marks and calculating the differencebetween them. For example, near the boundary of the cover glass mountedon the slide, the focus position of a focus reference mark covered withthe cover glass and the focus position of the focus reference mark thatis not covered with the cover glass are measured, and the differencebetween them is calculated as ΔL. When the change amount ΔL issubtracted from the δZ distribution, the δZ distribution becomes thedistribution of Z-direction positions of the slide surface based on theZ position of the slide origin. Note that in the above-described case(2) or (3), the δZ distribution may be obtained by subtracting ΔL fromthe focus position of a mark covered with the cover glass and directlyusing the focus position of a mark that is not covered with the coverglass. This makes it possible to measure the δZ distribution using allfocus reference marks whether a portion is covered with the cover glassor not.

Referring back to FIG. 27, if an origin mark or a focus reference markdoes not exist on the slide in step S17, the process advances to stepS22. Upon determining in step S22 that not a focus reference mark but anorigin mark exists on the slide, in step S23, the controller 501executes the same ΔΘ correction as in step S19. In step S24, thecontroller 501 executes the same slide origin detection positioning asin step S20. If neither a focus reference mark nor an origin markexists, the process advances from step S22 to step S25.

In step S25, the controller 501 (in which the position managementapplication is operating) transits to an observation mode. In step S26,the controller 501 notifies via the display 502 to switch the objectivelens to a low magnification, or switches the objective lens to a lowmagnification by sending a control command to the microscope. In stepS27, the controller 501 notifies the observer via the display 502 thatpreparation for observation position management is completed. Afterthat, it is convenient to move the stage and locate the observationposition (the center of the imaging field) on the slide origin.

Note that since the center of the visual field may slightly shift uponswitching the objective lens, an arrangement using a slide originaccording to an objective lens to be used is preferably provided. Toimplement this, for example, to detect the stage origin or the slideorigin every time the objective lens is switched, the controller 501starts executing processing shown in FIG. 48. In step S4801 of FIG. 48,the controller 501 determines whether the objective lens is switched.Switching of the objective lens can be detected by providing a sensorthat detects that the objective lens is switched by the revolver 127.Alternatively, switching of the objective lens may be detected bynotifying the controller 501 via a predetermined user interface that theuser has switched the objective lens.

Upon detecting switching of the objective lens, in step S4802, thecontroller 501 detects the stage origin again. This processing is thesame as in step S15 of FIG. 27. In step S4803, the controller 501determines whether an origin mark exists on the currently placed slide.If an origin mark exists, the slide origin is detected in step S4804. Asfor the presence/absence of the origin mark, the determination result instep S17 or S22 of FIG. 27 may be stored. Alternatively, the observationposition may be moved to the position where the origin mark shouldexist, and the presence/absence to the origin mark may be confirmed. Theslide origin detection is the same as described concerning step S20 ofFIG. 27. Since the slide does not change here, correction of the tilt ofthe slide surface and δZ distribution measurement are unnecessary.

Upon detecting that a slide is newly loaded, the process advances fromstep S4805 to step S4806. In step S4806, the processes of step S17 toS24 of FIG. 27 are executed for the newly loaded slide.

Note that if the mechanical accuracy of the revolver 127 is high, andthe slight shift of the field center or focus position mainly depends onthe magnification of the objective lens, the processing of step S4804may be omitted by obtaining a slide origin in correspondence with eachmagnification of the objective lens and storing it. Note that in thatcase, the controller 501, for example, obtains information representingthe magnification of the objective lens from the microscope body 100 viaa signal line (not shown), and stores the coordinates of the slideorigin obtained in step S4804 in the memory 512 in association with themagnification of the objective lens used at the time of detection. Upondetecting switching of the objective lens, if the coordinates of theslide origin corresponding to the magnification of the objective lensafter switching are stored in the memory 512, the controller 501 usesthe stored coordinates. If the slide origin corresponding to themagnification of the objective lens after switching is not stored, thecontroller 501 executes slide origin detection (step S4804) as describedabove.

When correction by the ΔC adapter 340, correction by the ΔΘ stage 600,and detection of the origin of the slide 700 have ended in theabove-described way, the controller 501 operates the microscope system10 in the observation mode. FIG. 40 is a flowchart for explainingprocessing of the controller 501 that controls position management ofthe observation position in the observation mode and still imagecapturing and recording using the digital camera 400.

First, in step S501, the controller 501 stores, in the memory, theposition (X-, Y-, and Z-coordinate values) of the slide origin based onthe stage origin, which is obtained in step S20 or S24 (FIG. 27)described above, as the coordinates of the slide origin. The slideorigin coordinates based on the stage origin will be referred to as (x0,y0, z0) hereinafter, and the observation position in the observationarea on the slide is managed based on the slide origin. That is, whenthe coordinate values of an observation position based on the stageorigin are represented by (x, y, z), (x0-x, y0-y, z0-z) are thecoordinate values of the observation position based on the slide origin.

In step S502, the controller 501 obtains the conversion coefficientbetween the X- and Y-coordinate values of the stage 200 and the actualdistance using the intervals of the center lines of two marks with aknown interval or lines or spaces which form one mark and have a knowninterval, the boundaries (edges) between lines and spaces, the widths ofthe lines or spaces, and the like. If an accurate correspondencerelationship (conversion coefficient) between the actual moving amountof the stage and the moving amount based on the scale coordinates isobtained, the actual distance can be calculated from the moving amountbased on the scale coordinates. The distance between two points in thesame observation screen without stage movement can also be grasped asthe actual distance by obtaining the correspondence relationship to theactual distance. The correspondence relationship is important whengrasping the actual size of the observation object. In this embodiment,the crosshatch X-axis 292, the crosshatch Y-axis 293, the crosshatch290, the Y-axis mark 703 of the slide, and the like can be used. Theobtained conversion coefficient (a first coefficient for the X- andY-coordinates) is stored in the memory 512. Note that as for theZ-coordinate, for example, the moving distance of the upper surface ofthe stage 200 by synchronous driving of the ΔZ lift units is measured bya linear gauge having a step difference in a predetermined thicknessdirection (Z direction), and the relationship between the change amountof the Z-coordinate and the moving distance is obtained, therebyobtaining the conversion coefficient (a first coefficient for theZ-coordinate) between the Z-coordinate value and the actual distance. Inthis case, the thus obtained first coefficient for the Z-coordinate isstored in, for example, the memory 512, like the first coefficient forthe X- and Y-coordinates.

Note that the first coefficient for the X- and Y-coordinates isobtained, for example, in the following way. First, the controller 501moves the stage 200 such that a predetermined position (for example, theobservation position) of the image sensor 401 is located at the centerof each of two marks or two lines (patterns) in one mark with a knowninterval out of the position reference marks of the XY crosshatch 213 orthe slide 700. Based on the difference between the coordinates of thepositions and the actual distance of the interval between the centerlines of the two marks or lines, the controller 501 calculates the firstcoefficient used to do conversion between the coordinate values and theactual distance. For example, in the small crosshatch located at theupper right corner of the crosshatch 290 of the XY crosshatch 213, theobservation position is sequentially set at the center of each of theleft Y-axis-direction mark and the right Y-axis-direction mark in theline width direction. The first coefficient is obtained based on thechange amount of the X-coordinate value and the actual distance (forexample, 0.5 mm) between the marks at this time. Alternatively, forexample, using the two 10 μm lines ((12 b) of FIG. 12) at the center ofthe crosshatch Y-axis 293 of the XY crosshatch 213, the observationposition is sequentially set at the center of each line by moving thestage 200. The first coefficient is obtained based on the change amountof the X-coordinate value and the actual distance (for example, 20 μm)between the lines at this time. Note that in this embodiment, the firstcoefficient is obtained for the X-coordinate. However, the firstcoefficient may be obtained for the Y-coordinate. In this embodiment,the first coefficient obtained for the X-coordinate is applied to theY-coordinate. However, the first coefficient for the X-coordinate andthat for the Y-coordinate may individually be measured and held, and theindividual first coefficients may be used for the X- and Y-coordinates.The two marks/patterns used to obtain the conversion coefficient neednot be included in the same visual field. For example, the rightmostY-axis-direction mark and the leftmost Y-axis-direction mark of thecrosshatch 290 may be used.

In step S503, the controller 501 executes still image capturing suchthat the two marks with the known interval are included in one image.The controller 501 obtains the conversion coefficient (secondcoefficient) between the pixel distance of the image sensor 401 and theactual distance using the obtained image and stores it in the memory.

The second coefficient is obtained, for example, in the following way.First, still image capturing is performed such that two lines in onemark with a known interval out of the position reference marks of the XYcrosshatch 213 or the slide 700 are included in the imaging field. Thecontroller 501 analyzes the still image, counts the number of pixelsbetween the two lines, and calculates the second coefficient used to doconversion between the pixel distance and the actual distance based onthe count value and the actual distance of the interval between the twolines. For example, imaging is performed such that the two outer linesof the crosshatch Y-axis 293 are included in the screen. The secondcoefficient is obtained from the number of pixels corresponding to theinterval between the lines and the known actual distance. Note that twolines in one mark are used above. However, two marks with a knowninterval may be used.

In step S504, the coordinate values (x, y, z) based on the stage originof the stage 200 obtained from the stage MPU 280 are converted intocoordinate values (x0-x, y-y0, z-z0) based on the slide origin, andposition management is performed by the coordinate values based on theslide origin. Here, (x0, y0, z0) are the coordinates of the slide originbased on the stage origin, which is stored in step S501.

Note that the user adjusts the Z-direction position by operating the ΔZknob 904. The rotation operation of the ΔZ knob 904 is converted by thestage MPU 280 into a driving signal to the ΔZ motors 913 configured tovertically move the ΔZ lift pins 914 of the ΔZ lift units 910, and thevertical movement of the stage 200 is controlled by the synchronousdriving of the ΔZ lift pins L1 to L3. As described above, theZ-coordinate (value Z) is [read value Z of Z linear scale 990 b]+[readvalue ΔZ of ΔZ linear scale 994 b]+[read value dZ of dZ linear scale 640b].

After that, when the user instructs the controller 501 to do still imagecapturing, the process advances from step S505 to step S506, and thecontroller 501 instructs the digital camera 400 to do still imagecapturing. Upon receiving the still image capturing instruction from thecontroller 501, the digital camera 400 in the observation modeimmediately captures a still image and transmits the image data to thecontroller 501. In steps S507 and S508, the controller 501 generates animage file including the image data received from the digital camera 400and stores it.

In step S507, additional information to be added to the image file isgenerated. The additional information includes the first coefficient,the second coefficient, and the observation position (the coordinatevalues (x0−x, y−y0, z−z0) based on the slide origin) described above.Note that a microscope ID used to identify the microscope in use, theobjective lens magnification at that time, a slide ID used to identifythe observation object slide, the δZ distribution information measuredin step S21 (FIG. 27), and the like may also be included as additionalinformation. Some pieces of the additional information (for example, themicroscope ID and the objective lens magnification) are notified fromthe microscope body 100 to the controller 501 via a signal line (notshown). Note that obtaining of the slide ID is implemented using, forexample, a barcode. In this case, a specific number is added as abarcode to a label attached to the label area 721. Alternatively, abarcode is directly printed on the slide glass in the label area 721 andread by a barcode reader (not shown) or the image sensor 401.

The δZ distribution information can have any form such as

-   -   the X- and Y-coordinates of the centers of focus units (at an        interval of 1 mm in this embodiment) that constitute a focus        reference mark and the measurement result of the focus position        δZ at that time,    -   a table of the X- and Y-coordinates of lattice points (the        center of a focus unit is located ahead a lattice point in the X        or Y direction) at an interval of 1 mm in the cover glass area        and the estimation results of δZ(x, y), or    -   the parameters of a curved surface that approximates the δZ        distribution.

That is, the δZ distribution information can have any form as long as itcan obtain a result that is the same as or similar to that of δZdistribution estimation in step S448.

In step S508, using the image data received in step S506, the controller501 generates an image file in which the additional informationgenerated in step S507 is inserted in the file header, and records it.FIG. 41 shows an example of the data structure of the image file. Theheader of the image file stores the above-described additionalinformation of image data 2510, that is, an observation position 2502, afirst coefficient 2503, a second coefficient 2504, a microscope ID 2505,an objective lens magnification 2506, a slide ID 2507, and δZdistribution information 2508 as well as a file name 2501. Theadditional information and the image data 2510 are thus recorded inassociation. Note that the additional information need not always bestored in the header of the image file and may be stored in the footer.The additional information may be recorded as another file, and linkinformation for reference may be added to the header or footer of theimage data. Note that as the observation position 2502, coordinatevalues based on the position indicated by the origin mark 701, that is,(x0-x, y-y0, z-z0) are recorded. If the origin mark 701 is dirty andunusable, the spare origin mark 702 is used. In this case as well, thecoordinate values are preferably converted into values based on anorigin position indicated by the origin mark 701 and recorded. Note thatsince the positional relationship between the origin mark 701 and thespare origin mark 702 is strictly defined, the reference position by theorigin mark 701 can be specified using the spare origin mark 702. Whenthe spare origin mark 702 is used, a position indicated by the spareorigin mark 702 (a position different from the position indicated by theorigin mark 701) may be used as the origin, as a matter of course. Inthis case, however, which origin mark is used needs to be recorded asadditional information together with the coordinates.

Note that in this embodiment, the skew detecting sensor 273 is providedto further improve the accuracy of position management of the stage 200.Skew detection and skew correction by the skew detecting sensor 273 willbe described later.

Synchronization between the stage 200 and still image file display bythe controller 501 will be described next. In this embodiment, since theobservation position ((x, y, z) coordinates) of a specimen on the slide700 can accurately be managed, the observation position of a still imagecaptured using the slide 700 at the time of imaging can easily bereproduced on the microscope side. In addition, movement of the stage200 can be instructed from the display 502 on which a still image isdisplayed, and a captured still image can selectively be displayed insynchronism with the movement of the stage 200.

FIG. 42 is a flowchart for explaining synchronization between stillimage display and movement control of the stage 200 by the controller501. FIG. 43 is a view for explaining synchronization between thedisplay screen and the position of the stage 200.

In step S601, the controller 501 displays the image data of a selectedimage file on the display 502. At this time, the controller 501 cangrasp the relationship between the size of one pixel of the image dataand the size of a display pixel of the display 502 (how many pixels onthe display correspond to one pixel of the image sensor) from thedisplay size of the image data on the display 502.

In step S602, the controller 501 moves the stage 200 and the ΔZ stage900 such that the observation position of the microscope aligns with theobservation position (coordinates) (xorg, yorg, zorg) based on the slideorigin and included in the additional information. Note that before stepS602, the slide 700 used to capture the displayed image is loaded to thestage 200, and slide origin detection is performed by the steps in FIG.27. The controller 501 also holds the coordinate values (x0, y0, z0) ofthe slide origin of the slide based on the stage origin. That is, fromthe observation position (coordinates) (xorg, yorg, zorg) based on theslide origin and the coordinates (x0, y0, z0) of the slide origin basedon the stage origin, the controller 501 calculates the coordinate valuesof the observation position based on the stage origin by (x0−xorg,y0+yorg, z0+zorg). In addition, the controller 501 replaces from thecoordinate values based on the stage origin with coordinate values basedon the initialization position of the stage, and controls the stage 200and the ΔZ stage 900. In this embodiment, position management inside thestage is done based on the initialization position of each stage.However, the above-described conversion of the coordinates of theobservation position from the coordinate values based on the slideorigin to the coordinate values based on the stage origin and then tothe coordinate values based on the initialization position may beperformed in the stage 200 and the ΔZ stage 900, as a matter of course.The observation position with respect to the slide 700 and theobservation position of the image that is being displayed on the display502 can accurately be aligned in this way. The controller 501 can alsoconvert the observation position (xorg, yorg, zorg) obtained from theimage file and the slide origin coordinates (x0, y0, z0) into an actualdistance using the first coefficient obtained from the image file, andinstructs the stage 200 and the ΔZ stage 900 to move using the actualdistance. Use of the actual distance makes it possible to cope with acase in with the microscope (stage 200) used to capture the still imageand the microscope (stage) currently in use are different. Uponreceiving the observation position based on the actual distance, thestage 200 and the ΔZ stage 900 convert the actual distance intocoordinate values using the first coefficient of their own notified fromthe controller 501 to the stage MPU 280, and the stage 200 is moved.

Note that if supporting the actual distance is a burden on the stage MPU280, the conversion from the actual distance to the coordinate valuesmay be executed by the controller 501 in which the position managementapplication is operating. For example, a stage driver (USB driversoftware for the stage MPU 280 if the stage MPU 280 and the control unit500 are connected via, for example, a USB) operating in the controller501 may execute the conversion on its behalf.

That is, as shown in FIG. 43, the CPU 511 of the controller 501 readsout the observation position coordinates (xorg, yorg, zorg) (based onthe slide origin) recorded as additional information from the header ofthe image file of a displayed image 1100. Note that as for the displayedimage 1100, for example, the CPU 511 obtains three-dimensionalcoordinates (x, y, z) input by the user via an operation unit (notshown) connected to the controller 501, reads out the image file of theheader including the three-dimensional coordinates as the observationposition coordinates, and displays it on the display 502. Thecoordinates are converted into the coordinates (Lx, Ly, Lz) of an actualdistance using the first coefficient of the stage at the time ofrecording, which is recorded as additional information (step S701 inFIG. 43). The actual distances Lx, Ly, and Lz from the slide origin tothe observation position are thus obtained. The coordinates (Lx, Ly, Lz)represented by the actual distances are converted into stage coordinatevalues using the first coefficient of the stage currently in use,thereby obtaining the coordinates (xs, ys, zs) of the observationposition (based on the slide origin) corresponding to the stage in use.Then, the observation position (x, y, z) based on the stageorigin=(x0−xs, y0+ys, z0+zs) is obtained from the slide origincoordinates (x0, y0, z0) based on the stage origin of the stagecurrently in use (step S702). The controller 501 instructs to move thestage 200 and the ΔZ stage 900 to locate the imaging center of the imagesensor 401 at the thus obtained coordinates (x, y, z) of the observationposition based on the stage origin (step S703). Note that in anarrangement that does not execute conversion to an actual distanceconcerning the Z-coordinate, zorg=zs.

Note that as described above, the stage 200 is moved in the Z directionby synchronously driving the three ΔZ lift units 910. With theabove-described operation, the observation position of the displayedimage and the observation position of the slide 700 in the microscopecan be aligned in the three, X, Y, and Z directions. That is, theobservation position used to capture the still image is correctlyreproduced in the three-dimensional space.

Next, the controller 501 determines whether an observation positionmoving instruction is generated on the screen of the display 502 (stepS603) and whether a movement of the stage 200 and the ΔZ stage 900 hasoccurred (step S606). If an observation position moving instruction isgenerated on the screen of the display 502, the process advances fromstep S603 to step S604. Note that concerning the X and Y directions, theobservation position moving instruction on the screen is made bydetecting the start point and the end point of a drag operation by amouse. In step S604, for example, in FIG. 43, when a start point 1001and an end point 1002 of drag by the mouse are detected, a vector 1003having the moving direction and moving amount of the screen is obtainedas an XY-direction moving instruction. This means moving the observationposition (xorg, yorg, zorg) (based on the slide origin) of the displayedimage 1100 by an amount corresponding to the vector 1003.

That is, upon detecting the XY-direction screen moving instruction onthe display 502, the controller 501 converts the moving amounts in the Xand Y directions into the moving amounts of the XY stage. For example,referring to FIG. 43, the display pixel distance on the display 502 isobtained from the vector 1003. The display pixel distance is representedby an X-direction moving amount Δxdisp and a Y-direction moving amountΔsp, which are converted into pixel distances (Δxpix, Δypix) on theimage sensor 401 (step S711). Next, the controller 501 converts thepixel distances into actual distances (ΔLx, ΔLy) using the secondcoefficient (step S712). The controller 501 converts the actualdistances into moving amounts (Δx, Δy) of the stage using the firstcoefficient (obtained in step S502 of FIG. 40) of the currently usedstage 200 (step S713). When the stage 200 is moved from the currentposition (x, y) by the thus obtained moving amounts (Δx, Δy) (stepS605), the stage 200 moves as indicated by a vector 1004. As a result,the new observation position (the observation position moved by thevector 1003) on the display 502 synchronizes with the observationposition (the observation position moved by the vector 1004) by thestage 200.

Note that since the movement in the Z direction is not instructed by theoperation of the mouse, the stage 200 does not move in the Z direction.Note that when the stage 200 moves in the X and Y directions, theobservation position from the slide surface may be maintained using theδZ distribution. In this case, to maintain the height of the observationposition from the slide surface, a change in the Z-coordinate of theslide surface according to the movement of the X- and Y-coordinates ofthe stage 200 from (x, y) to (x+Δx, y+Δy) is obtained by δZ=δZ(x+Δx,y+Δy)−δZ(x, y) based on the δZ distribution of the slide. Along with themovement of the stage 200 to (x+Δx, y+Δy), the stage 200 is moved in theZ direction by the change amount of δZ. The observation position in theZ direction is thus maintained almost at a predetermined distance fromthe slide surface. Note that the user may be able to set whether to movethe stage 200 while maintaining a predetermined Z-coordinate or move thestage 200 while maintaining the height of the observation position fromthe slide surface.

Note that as for the moving instruction on the screen in step S603, thedrag operation of the mouse is used for the movement in the X and Ydirections, as described above. On the other hand, the movinginstruction in the Z direction is done by, for example, displaying upand down arrows on the display screen and operating them by the mouse.In this case, when the mouse accesses the up arrow, the stage moves inthe Z-axis positive direction (upward). When the mouse accesses the downarrow, the stage moves in the Z-axis negative direction (downward). Themovement of the stage 200 in the Z direction in this case is implementedby synchronously driving the ΔZ lift pins 914 of the three ΔZ lift units910 of the ΔZ stage 900. In this case, as for the limitation of theupward movement of the stage 200, for example, the δZ distribution δZ(x,y) of the slide surface+10 μm is set. This is because the specimenthickness varies but never exceeds 10 μm. As for the limitation of thedownward movement of the stage 200, for example, the δZ distributionδZ(x, y) is set. Alternatively, an interface that displays a slider baror a knob and instructs the movement in the Z direction by the mouse orthe like may be used. In this case, the upper and lower limit valuesare, for example, “the δZ distribution δZ(x, y) of the slide surface+10μm” and “the δZ distribution δZ(x, y) of the slide surface”,respectively.

On the other hand, when the stage 200 and the ΔZ stage 900 are moved byoperating the X knob 201, the Y knob 202, and the ΔZ knob 904 or inaccordance with an (electric) moving instruction by a console (notshown) for the stage 200 and the ΔZ stage 900, the process advances fromstep S606 to step S607. In step S607, the controller 501 moves thedisplay on the display 502 in accordance with the moving amount of thestage. As for the movement in the X and Y directions, the process ofstep S604 described above is executed in a reverse direction. That is,referring to FIG. 43, if the stage 200 is moved as indicated by thevector 1004, the controller 501 converts the moving amounts (Δx, Δy)into the actual distances (ΔLx, ΔLy) using the first coefficientobtained in step S502 (step S713). Then, the controller 501 converts theactual distances in the X and Y directions into the pixel distances(Δxpix, Δypix) using the second coefficient recorded in the additionalinformation of the currently displayed image file (step S712). The pixeldistances are converted into the display pixel distances (Δxdisp,Δydisp) on the display 502 (step S711). Control is performed to move theimage by the vector 1003.

Note that when moving in the X and Y directions, as for the Z-directionposition of the stage 200, for example, automatic adjustment to maintainthe observation position in the Z direction at a predetermined distancefrom the slide surface is performed. In this automatic adjustment, achange in the value of the δZ distribution caused by the movement of theX- and Y-coordinates of the stage 200 from (x, y) to (x+Δx, y+Δy), thatis, δZ=δZ(x+Δx, y+Δy)−δZ(x, y) is obtained. The stage 200 is moved inthe Z direction by δZ by controlling the ΔZ stage 900. The observationposition in the Z direction is thus maintained at a predeterminedposition from the slide surface. Note that the Z-coordinate of the stage200 may be maintained without performing the automatic adjustment. Theuser may be able to set whether to perform automatic adjustment.

As for the movement in the Z direction, the Z-coordinate of theobservation position moves by the manual operation of the ΔZ knob 904 orin accordance with an (electric) moving instruction by a console (notshown) for the ΔZ stage 900. At this time, as for the limitation of theupward movement, for example, the δZ distribution δZ(x, y) of the slidesurface+10 μm is set. This is because the specimen thickness varies butnever exceeds 10 μm. As for the limitation of the downward movement, forexample, the δZ distribution δZ(x, y) is set.

As for the movement in the X and Y directions, in step S608, the displaycontents are updated in accordance with the vector 1003 obtained in stepS604 or S607. In this case, the display range of the currently displayedimage 1100 is updated to the display range of an image 1101. However, ofthe image data in the display range of the image 1100, only the imagedata of a portion overlapping the display range of the image 1101 can bedisplayed in the display range of the image 1101. That is, a portionthat does not overlap the image 1100 is displayed as a short (blank)portion on the display screen of the image 1101. Hence, the image isobtained from another image file including the short portion andcomposed. The image file to be used is selected from image files withcommon objective lens magnification, slide ID, and microscope ID basedon the observation position. Note that if an image file corresponding tothe observation position does not exist as the result of stage movement,the mode may automatically switch to live view. If an image file thatcan be composed exists (NO in step S609), the image file is selected,and image composition is performed using it (step S611).

If an image file that can be composed does not exist, a new image isneeded for image display (YES in step S609). Hence, the controller 501generates a new image file by performing still image capturing after themovement of the stage 200, and displays it or composes it with theexisting overlap portion so as to compensate for the above-describedshort portion (blank portion) (steps S610 and S611). Note that both in acase in which a new image file is displayed and in a case in which animage is composed to compensate for the short portion, a composed imageof the images 1100 and 1101 is obtained. However, the method ofcomposing the images 1100 and 1101 is not particularly limited. Forexample, part of the image 1101 may be composed with the periphery ofthe image 1100, part of the image 1100 may be composed with theperiphery of the image 1101, or the composition may be done at aposition to divide the image overlap region to ½. With this compositionprocessing, a seamless observation image of the subject on the slide canbe obtained. When an image is sequentially composed with the shortportion generated by the movement of image (or XY stage), the composedimage grows during movement of the observation position.

As for the movement in the Z direction, the display range of thecurrently displayed image 1100 is updated to the image at the new Zposition. If an applicable image file exists, the applicable image fileis selected, and the image is updated using it. If an applicable imagefile does not exist, a new image is needed for image display. Hence, thecontroller 501 generates a new image file by performing still imagecapturing after the movement of the stage 200 in the Z direction, anddisplays it.

As described above, according to this embodiment, since the observationposition can be managed using coordinates based on the referenceposition on the slide, the observation position can easily bereproduced. That is, as for the position accuracy, the movement of thestage in the X and Y directions can be controlled at an accuracy of 0.1μm by accurately detecting the position using the XY two-dimensionalscale plate 210. Concerning the Z direction, the movement in the Zdirection can be controlled at an accuracy of 0.1 μm by accuratelydetecting the position using the Z linear scale 990 b, the ΔZ linearscale 994 b, and the dZ linear scale 640 b. Additionally, concerning theZ direction, tilt correction for the stage and the slide surface andgrasping of the δZ distribution are performed. This makes it possible todefine or reproduce the correct observation position in the planedirection (XY) and thickness direction (Z) of the specimen inpathological diagnosis. That is, reproduction of the observationposition of an ROI, which conventionally depends on a memory, can bedone correctly and quickly. In addition, since the ΔΘ stage 600 isemployed, even after the slide is temporarily unloaded from the stage,the influence of the placement state (for example, rotational shift) ofthe slide can be reduced, and the observation position can correctly bereproduced.

As described above, in observation position management, since theposition coordinates of a display image and the position coordinates onthe stage accurately synchronize, the observer can always accuratelyknow the coordinate values of the observation position based on theslide origin. The course of the movement of the observation position canbe recorded by predetermined application software. An arbitraryobservation position can accurately be reproduced by designatingcoordinate values. When a recorded evidence image is reproduced, theobservation position on the slide corresponding to the displayed imagecan correctly be re-observed by the microscope. This function isexecuted when the slide ID recorded in the additional information of thedisplayed image file matches the ID read from the label of the slidecurrently placed on the stage.

The controller can thus record the moving path of the observationposition (x, y, and z-coordinates) in diagnosis as a path log inassociation with the slide ID. If the objective lens or the like ischanged, or the ROI is captured midway, the information can usefully berecorded in addition to the path log. The controller can also reproducethe process of observation based on the path log. This is implemented byselecting a corresponding path log based on the slide ID, automaticallydriving the stage according to the path, and controlling the objectivelens of the microscope.

Accordingly, processing that is supposed to be valuable as pathologicaldiagnosis can be implemented in morphological diagnosis, for example, itis possible to superimpose the images of a plurality of slides generatedfrom a plurality of tissue slices adjacent in the thickness directionand observe a change in the thickness direction of the tissue. Asadditional processing necessary in this case, for example, the pluralityof images at the same position coordinates of the plurality of slidesare superimposed in the vertical direction, and a feed operation in thevertical direction (thickness direction) is performed to switch thedisplay image as needed. Alternatively, the images of the plurality ofslides may be displayed side by side, and the same position may beindicated by a predetermined mark, or the observation portion may bemoved synchronously in the plurality of images. Otherwise, when morecontinuous tissue slice images are used, 3D display can be implementedusing an existing 3D algorithm. These processes are executed by softwareon the controller 501.

In functional diagnosis, the controller 501 can display a plurality ofimages in different staining on the display 502 in a superimposed mannerby similar software processing. For example, it is possible to observe aslide that has undergone morphological staining, after that, applyfunctional staining to the slide and observe it, and compose anddisplay, at a predetermined accuracy, microscope images captured in themorphological staining and the functional staining.

For example, the microscope system obtains the image 1100 (first image)of an observation object on a first slide, which is in a first staining.This image is stored in the memory (not shown) of the controller 501.After that, the staining of the first slide is changed to a secondstaining, and the slide is placed on the ΔΘ stage 600 of the microscopesystem again. The microscope system captures the observation object inthe second staining again and obtains an image (second image). At thistime, the CPU 511 reads out the image 1100 (first image) from the memoryand obtains the observation position coordinates (xorg, yorg, zorg)stored in the header of the image 1100. The microscope system performsthe above-described stage position control based on the values of theobservation position coordinates and sets the observation position ofthe second image. This allows the first image and the second image tohave the same imaging range. The controller 501 displays the first imageand the second image on the display 502, as described above. By thestage control and display control, the pathologist can easily observethe same observation object in different staining while reducing thelabor to manually adjust the stage.

Alternatively, it is possible to display morphological images ofcontinuous tissue slices and (a plurality of) functional images byfunctional staining in a superimposed manner and compare and observe amorphological atypism and a function change. These processes aresupposed to be valuable as pathological diagnosis but are conventionallyunimplementable.

In addition, the array of the elements of the image sensor, the X and Ydirections of the stage, and the X and Y directions of the slide cancorrectly be aligned. It is therefore possible to eliminate therotational shifts of a plurality of still images and easily compose theplurality of captured images at different observation positions.

Coordinates can be managed via an actual distance. Hence, even if thestage 200 with a different relationship between the coordinates and theactual distance is used, the observation position can correctly bespecified. Note that the actual distance may be used for the coordinatevalues of the observation position (based on the slide origin) recordedas additional information, as a matter of course. In this case, theabove-described first coefficient (the conversion coefficient betweenthe coordinate values of the stage 200 and the actual distance) may beomitted from the additional information. In addition, informationrepresenting whether the description is based on the actual distance oris based on the distance (coordinate value) on the stage mayadditionally be recorded together with the coordinate values.

A form in which the digital camera 400 is mounted has been describedabove. However, the image sensor 401 may be incorporated in themicroscope body 100. In this case, rotational shift correction by the ΔCadapter 340 can be omitted.

Note that in the above-described operation procedure, the digital camera400 may have a setting to set the color live mode when powered on or afunction of implementing image processing unique to the measurement modein the live mode as well. The digital camera 400 may have a function ofperforming still image capturing from any live mode and thenautomatically returning to the live mode.

Note that in the above-mentioned operation procedure, allotment ofvarious kinds of image processing in the measurement mode of the digitalcamera and various kinds of processing such as strip width setting,barycenter calculation, and angle-of-view determination in the CPU hasspecifically been described. However, some or all of the processes maybe implemented by another apparatus.

In the above-described embodiment, only a slide having a normal size (1inch*3 inches) has been handled. However, this also applies to a slidewith a larger size (2 inches*3 inches), as a matter of course.

In the above-described embodiment, focusing is needed in some cases inangle-of-view determination (steps S206 and S305), still image capturing(steps S209, S308, S401, and S406), and the like of thehigh-magnification objective lens. Such focusing is implemented bysynchronously driving the lift pins 914 by the ΔZ lift units 910provided on the ΔZ stage 900.

Additionally, when a general slide without a position reference marksuch as an origin mark is used, position management of the stage isperformed based on the crosshatch origin 291 that can serve as anaccurate stage origin position. That is, coordinate management of theobservation position in the Y direction based on the crosshatch originis implemented by alignment of the stage origin in the X and Ydirections using the crosshatch origin 291. The position in the Z-axisdirection in a case in which a focus is placed on the crosshatch origin291 is used as the reference of position management of the observationposition in the Z-axis direction. According to this method, the accuracygreatly rises as compared to coordinate management based on the initialposition of the stage containing a mechanical error by the X, Y, and Zinitial position marks and the X, Y, and Z initial position sensors. Asdescribed above, even if the slide does not have the origin mark,accurate alignment is performed by the stage origin (crosshatch origin291). It is therefore possible to perform position management byexploiting accurate position management capability by the stage 200, theΔZ stage 900, and the adapter unit 300 (ΔC adapter 340). For example, ina case in which the stage 200 is powered off and then powered on againwhile keeping a slide without an origin mark placed on it, alignment ofthe stage origin is accurately executed in step S15. Hence, moreaccurate position management can be continued.

For a slide that has an origin mark but no focus reference mark, the δZdistribution cannot be measured. The controller 501 performs positionmanagement assuming that the δZ distribution in the entire cover glassarea 722 equals the focus position of the origin mark, that is, δZ(x,y)=0.

As described above, an accuracy of 0.1 μm is implemented as the positionmanagement accuracy by the Z linear scale 990 b, the ΔZ linear scale 994b, and the dZ linear scale 640 b. This is because a 100× objective lenshas a focal depth of, for example, about 0.1 μm for ultraviolet lightthat has the shortest wavelength (200 nm) observable by an opticalmicroscope, and it is adequate to set the target value of the positionmanagement accuracy in the vertical (Z) direction to 0.1 μm, like the Xand Y directions. When position management at an accuracy of 0.1 μm inthe Z direction is implemented, the observation position within a tissueslice can be managed at an accuracy of 0.1 μm. This can implement imagecomposition (3D image formation) in the vertical direction by Z stackimaging of a tissue slice at an interval of, for example, 0.1 μm.Additionally, in continuous tissue slice slides, it is possible toperform Z stack imaging at an interval of 0.1 μm in the Z direction atthe same XY position of the slides and superimpose the images byposition synchronization in the X and Y directions. A 3D image of atissue in a thickness corresponding to the created slides can thus becomposed by continuous slices. That is, when a tissue image in eachslide is captured by Z stack, and the Z stack images of the slides arefurther composed for continuous tissue slices, composition of a 3D imageof the entire tissue in a thickness corresponding to the created slidesis implemented.

Note that at the time of Z stack, when a tilt in a visual field isremoved by controlling the dZ lift pins M1 to M3 based on an estimatedδZ distribution, Z stack along the slide surface is implemented in thevisual filed (observation range). In this case, the controller 501decides the slant of the upper surface of the slide in the observationrange by the microscope body based on the estimated δZ distribution. Forexample, a plane is approximated from the δZ distribution in theobservation range, and the slant of the approximated plane is decided,thereby obtaining the slant of the upper surface of the slide. Thecontroller 501 drives the dZ lift pins and adjusts the slant of theslide placement surface to eliminate the thus obtained slant of theupper surface of the slide.

Note that display on the display 502 by the CPU 511 of the controller501 may be done by simultaneously or selectively displaying a pluralityof images obtained by capturing a plurality of observation objects. Inthis case, a plurality of images obtained by capturing an observationobject in different staining may be displayed. Alternatively, a firstimage and a second image obtained by capturing two observation objectsthat are sliced from the same specimen and are adjacent in a directionorthogonal to the slice surface may be displayed on the display 502 bythe CPU 511 of the controller 501.

As shown in (49 a) of FIG. 49, focus reference marks 4902 to 4905 may bearranged on four sides around the lower surface (a side facing the uppersurface of a slide) of a cover glass 4901. The focus reference marks4902 to 4905 are the same as the focus reference marks 704 to 707 of theslide 700. When the focus reference marks 4902 to 4905 are used, the δZdistribution on the lower surface of the cover glass can be measured,like the δZ distribution on the slide 700. The Z-coordinate (zf1) of theupper surface of the slide 700 at the observation position and theZ-coordinate (zf2) of the lower surface of the cover glass 4901 can thusbe obtained, as shown in (49 b) of FIG. 49. From the difference(zf2−zf1) between the values, the thickness (including the influence ofa transparent mounting agent that fixes the cover glass on the slidesurface) of a tissue slice 4910 at the observation position can beknown.

Note that as for the values zf1 and zf2, the expected value of thethickness of the tissue slice 4910 can be obtained even for a specimenregion without the focus reference marks by using the δZ distributionand δZ1 on the slide surface and the δZ distribution and δZ2 on thelower surface of the cover glass. In addition, zf1 and zf2 can be usedto set the division step of imaging in step imaging (Z stack) in the Zdirection. For example, using “the value (Δzf) of a focal depthcorresponding to the objective lens used for observation” and “theZ-coordinates zf2 and zf1 of the upper and lower ends of the tissueslice”, imaging is performed while moving from zf1 in the Z direction byΔzf. Imaging is performed at a position at which the Z position exceedszf2 for the first time. After recording, the processing is ended.Alternatively, the integer part of ((zf2−zf1)/Δzf)+1 is set to thenumber n of divisions and (zf2−zf1)/n is set to the division step in theZ direction. For example, imaging is sequentially performed for eachdivision step from the upper surface (zf1) of the slide to the lowersurface (zf2) of the cover glass, and images are recorded. In theabove-described way, the position of the upper surface of the slide andthe position of the lower surface of the cover glass at the imagingposition are obtained based on the estimated distribution. While settingthe position of the upper surface of the slide to the lower limit andthe position of the lower surface of the cover glass to the upper limit,imaging by the digital camera 400 is performed at a predeterminedinterval in the Z-axis direction. Appropriate stack imaging can thus beperformed.

A plurality of images obtained in the above-described way are inposition synchronization in the X and Y directions, as described above.Hence, the images can be composed by superimposing them in the verticaldirection. For example, a 3D image can also be constructed. Note thatthe axial direction of each focus reference mark on the cover glass is,for example, different by 90° from the axial direction of acorresponding focus reference mark on the slide. Accordingly, even ifthe focus reference mark on the upper surface of the slide and the focusreference mark on the lower surface of the cover glass overlap, whichfocus unit has the focus can be identified based on the difference ofthe direction. The above-described position reference marks and focusreference marks of the slide are arranged at a distance equal to or morethan the angle of view of a low-magnification objective lens. When thecover glass is placed at a predetermined position of the slide, thereference marks of the slide and the focus reference marks of the coverglass are arranged at a distance equal to or more than the angle of viewof a low-magnification objective lens.

When the above-described accurate Z position management is implemented,the following added values of the system are provided. For example, thenecessity of retreat (an operation of moving the stage 200 downward) toavoid a collision in rotation of the objective lens can be obviated. Theworking distances of objective lenses (the distances from the distalends of objective lenses to the upper surface of the cover glass) are,for example, 13 mm for 4×, 3.1 mm for 10×, 0.6 mm for 20×, 180 μm for40×, and 130 μm for a 100× immersion lens. When the movement upper limitof the Z-coordinate is set to 10 μm (specimen)+170 μm (the maximumthickness of cover glass), the objective lens and the upper surface ofthe cover glass are spaced apart by about 130 μm−10 μm=120 μm even in a100× objective lens. Hence, when switching the objective lens, theobjective lens does not collide against the upper surface of the coverglass.

In the Z-direction operation, a collision of the objective lens againstthe observation surface can be avoided. For example, when adjusting theZ position by a user operation of the ΔZ knob 904, the controller 501prevents the stage from moving from the slide Z origin more than apredetermined amount. Alternatively, when adjusting the Z position ofthe Z base 130 by operating the Z knob 125, a warning may be given, orthe movement may forcibly be stopped if the Z position of the slideglass on the stage 200 moves close to the objective lens from the slideZ origin more than a predetermined amount.

The above description has been made without including a processingoperation concerning the skew detecting sensor. In this embodiment, theskew detecting sensor 273 is provided to further improve the accuracy ofposition management of the stage 200. The role of the skew detectingsensor and skew correction processing will be described below.

The position management plane stage 220 on which the slide 700 is placedmay generate a small axial fluctuation on the micrometer order whendriving the stage 200 in the X- and Y-axis directions. This results froma small skew or meandering (complex skew) caused by a small distortionof the stage mechanism and the machining accuracy of the X- and Y-axiscross roller guides. Such a small axial fluctuation on the micrometerorder may consequently appear as a small rotational shift as shown in(45 a) of FIG. 45.

In (45 a) of FIG. 45, reference numeral 2102 denotes a position of theposition management plane stage 220 before movement; and 2103, aposition of the position management plane stage 220 with a rotationalshift after movement. In FIG. 45, (45 b) shows the state of the position2103 in more detail. In FIG. 45, (45 b) shows a position 2104 of theposition management plane stage 220 including a slight rotational shiftwith respect to the stage base 260 on which the X-axis sensor 271 andthe skew detecting sensor 273 are disposed. In FIG. 46, (46 a) shows therelationship between the X-axis sensor 271 in (45 b) of FIG. 45, thecenter of the observation field 170, and an X-direction axis 1105passing through the observation field 170 at the position 2104 of theposition management plane stage 220.

As shown in (46 a) of FIG. 46, the axis 1105 shifts in the verticaldirection with respect to a line 1106 that passes through the center ofthe observation field 170 and the detection center of the X-axis sensor271. In this example, the axis 1105 is assumed to shift in, for example,the vertical direction by 2 μm at the detection center of the X-axissensor 271. Let t be the vertical shift amount, and d be the smallrotational shift angle generated by the shift. A change e in theX-coordinate by the X-axis sensor 271 according to the rotational shiftis 0.025 nm. This change is undetectable because it is much smaller thanthe resolution (10 nm) of the X sensor. In this regard, an example ofthe formula of e is given byd=ASIN(t/L1),e=L1*(1−COS d)

where L1 is the distance between the center of the observation field 170and the detection center of the X-axis sensor 271. In this example,L1=80 mm. That is, to obtain an accurate coordinate of the center of theobservation field 170, the X-axis sensor 271 is disposed on the axisthat passes through the center of the observation field 170. The X-axissensor 271 is never affected by the small rotational shift, andtherefore, cannot detect the small rotational shift.

On the other hand, the skew detecting sensor 273 is spaced apart fromthe axis passing through the center of the observation field 170 anddisposed vertically above the X-axis sensor 271, and therefore, candetect the rotational shift. In FIG. 46, (46 b) is a view for explaininga change amount in the skew detecting sensor 273. In 30D, f representsthe amount of a change in the X-coordinate in the skew detecting sensor273 with respect to the rotational shift d. Based on a distance S (inthe example of 30D, 40 mm) between the X-axis sensor 271 and the skewdetecting sensor 273, f is calculated byf=(S ² +L1²)^(1/2)(COS D−COS(D+d))

where D=ATAN(S/L1), and d=ASIN(t/L1)

According to this formula, f is obtained as 1 μm with respect to theshift of 2 μm (t) in the vertical direction. This change amount issufficient relative to the sensor resolution of 10 nm. According to theskew detecting sensor 273, the small rotational shift angle d of theposition management plane stage 220 can be detected.

When the position management plane stage 220 has a small rotationalshift, the placed slide 700 also has the small rotational shift, and thecaptured image at the position 2103 includes the rotational shift. InFIG. 47, (47 a) shows the display images of the captured images of theslide 700 at the positions 2102 and 2103 shown in (45 a) of FIG. 45. In(47 a) of FIG. 47, reference numeral 2107 denotes a display image of thecaptured image at the position 2102; and 2108, a display image of thecaptured image at the position 2103. The display image 2108 has arotational shift and causes a little mismatch when composed with thedisplay image 2107 based on the position coordinates. Accordingly, asmall rotational shift occurs when synchronizing the display screen withthe position of the stage 200. In this embodiment, the target positionmanagement accuracy is 0.1 μm, and skew correction needs to be performedso the rotational shift does not cause a vertical shift more than 0.1 μmin a predetermined observation range (for example, the observationobject region 205). This rotational shift needs to be corrected asneeded in accordance with the movement of the stage using apredetermined threshold as a determination criterion, unlike therotational shift (ΔC) of the digital camera 400 and the rotational shift(ΔΘ) of the slide itself when placing the slide, which can be eliminatedby performing correction only once for a predetermined target.

For example, when the vertical shift amount t=0.1 μm, f is calculated as50 nm according to the above-described formula. Hence, in thisembodiment, to implement the position management accuracy of 0.1 μm,f=50 nm is used as the threshold to determine whether to perform skewcorrection. This example of the threshold is applicable in a case inwhich the distance L1 between the center of the observation field 170and the detection center of the X-axis sensor 271 is 80 mm. On the otherhand, the distance from the origin mark 701 to the far end of the slide700 is 53 mm (see (23 a) of FIG. 23), which is smaller than 80 mm.Hence, the coordinates (x0−x, y−y0) of the center of the observationfield 170 based on the slide origin have a position management accuracyof 0.1 μm or less.

For example, when initializing the XY stage, the skew detecting sensor273 resets the coordinates to zero. After that, the controller alwaysmonitors the difference value between the X-coordinate value detected bythe X-axis sensor 271 and the X-coordinate value detected by the skewdetecting sensor 273 as the change amount (f). Note that the changeamount (f) is zero at the time of initialization. If a difference valueis generated later in detection of the slide origin or detection of thecrosshatch origin 291, the controller newly sets the difference value asa reference value, and always monitors the X-coordinate change amount(f) of the skew detecting sensor 273 from the newly set reference value.If the change amount f is equal to or less than the threshold (forexample, 50 nm), the controller determines that no skew exists, andperforms the above-described processes shown in FIGS. 27 and 40 to 43.If the change amount f exceeds the threshold, the controller determinesthat a skew exists. The controller executes skew processing to bedescribed below and then performs the above-described processes shown inFIGS. 27 and 40 to 43.

In the skew processing, first, the rotational shift angle d is obtainedby a formula in a reverse direction represented byd=ACOS(COS D−f/L2)−D,

where D=ATAN(S/L1), and

L2 is the distance between the center of the observation field 170 andthe detection center of the skew detecting sensor 273. The display image2108 is rotated by the rotational shift angle d around the center(corresponding to the center of the observation field 170) of thedisplay image as a rotation axis. That is, as shown in (47 b) of FIG.47, the display image 2108 including a rotational shift shown in (47 a)of FIG. 47 is rotated by d to obtain a display image 2109. The rotationdirection is reverse to the rotational shift of the position 2103 of theposition management plane stage 220 shown in (45 a) of FIG. 45. With theabove-described skew processing, the small rotational shift caused by asmall distortion of the stage mechanism, a small axial fluctuation ofthe X- and Y-axis cross roller guides, or the like is corrected, and anecessary position management accuracy is ensured.

Note that as another example of the threshold, shift amounts generatedby rotation of the center of the observation field 170 based on theorigin mark 701 may be calculated from the rotational shift angle dobtained from the change amount f, and whether the shift amounts in theX and Y directions are equal to or less than 0.1 μm may be determined.As another example of skew correction, when the skew amount exceeds thethreshold, the position may be moved to the latest position where theskew amount is equal to or less than the threshold, an image may becaptured at the position, and the moving amount may be corrected to doposition synchronization. If the machining accuracy improves, and thefrequency of skew correction becomes low, skew detection may be used asstage fault detection without performing skew correction.

The embodiment of the present invention also includes an apparatus forexecuting the following processing and a method of the processing. Thatis, the processing is processing of supplying software (program) thatimplements the functions of the above-described embodiment to the systemor apparatus via a network or various kinds of storage media, andreading out and executing the program by the computer (or CPU or MPU) ofthe system or apparatus.

Embodiment(s) of the present invention can also be realized by acomputer of a system or apparatus that reads out and executes computerexecutable instructions (e.g., one or more programs) recorded on astorage medium (which may also be referred to more fully as a‘non-transitory computer-readable storage medium’) to perform thefunctions of one or more of the above-described embodiment(s) and/orthat includes one or more circuits (e.g., application specificintegrated circuit (ASIC)) for performing the functions of one or moreof the above-described embodiment(s), and by a method performed by thecomputer of the system or apparatus by, for example, reading out andexecuting the computer executable instructions from the storage mediumto perform the functions of one or more of the above-describedembodiment(s) and/or controlling the one or more circuits to perform thefunctions of one or more of the above-described embodiment(s). Thecomputer may comprise one or more processors (e.g., central processingunit (CPU), micro processing unit (MPU)) and may include a network ofseparate computers or separate processors to read out and execute thecomputer executable instructions. The computer executable instructionsmay be provided to the computer, for example, from a network or thestorage medium. The storage medium may include, for example, one or moreof a hard disk, a random-access memory (RAM), a read only memory (ROM),a storage of distributed computing systems, an optical disk (such as acompact disc (CD), digital versatile disc (DVD), or Blu-ray Disc (BD)™),a flash memory device, a memory card, and the like.

While the present invention has been described with reference toexemplary embodiments, it is to be understood that the invention is notlimited to the disclosed exemplary embodiments. The scope of thefollowing claims is to be accorded the broadest interpretation so as toencompass all such modifications and equivalent structures andfunctions.

This application claims the benefit of Japanese Patent Application No.2015-241640, filed Dec. 10, 2015 which is hereby incorporated byreference herein in its entirety.

The invention claimed is:
 1. A microscope system comprising: amicroscope body; a camera connected to an observation optical system ofthe microscope body, the observation optical system including anobjective lens having an optical axis; and an XY stage including a slideplacement surface on which a slide of an observation object is placed,the XY stage being configured to move in an X-axis direction and aY-axis direction that are orthogonal to each other, wherein the XY stagecomprises an XY two-dimensional scale plate, wherein the XYtwo-dimensional scale plate comprises: (1) a first mark configured toprovide X-axis direction axis information and Y-axis direction axisinformation of the XY stage; and (2) a second mark including a pluralityof focus marks arranged in a rectangular shape, wherein each of theplurality of focus marks includes a plurality of pairs of lines arrangedin parallel and coaxial, with the same line width in a pair anddifferent line width from pair to pair, and wherein the plurality offocus marks are arranged in the rectangular shape such that threespecific focus points in respective association with three apexes in atriangle can be specified in the second mark, and the three specificfocus points are configured such that a slant of the XY stage withrespect to the optical axis is arithmetically obtained based on three Zcoordinate values in association with the three specific focus pointswhich are under a focal condition of the camera.
 2. The system accordingto claim 1, wherein the second mark forms the rectangular shape which isformed from (a) two parallel sides each having a predetermined widthalong the X-axis direction and (b) two parallel sides each having apredetermined width along the Y-axis direction.
 3. The system accordingto claim 1, wherein the XY two-dimensional scale plate is disposed onthe XY stage such that a rectangular plane formed by the second markbecomes parallel to the slide placement surface of the XY stage.
 4. Thesystem according to claim 1, wherein the plurality of focus marksincludes at least three focus marks including (a) two focus marks spacedapart by a predetermined distance along the X-axis direction and (b) onefocus mark located at a position spaced apart by a predetermineddistance from a side formed by the two focus marks.
 5. The systemaccording to claim 1, further comprising: a Z base configured to movethe XY stage in a Z-axis direction which aligns with the optical axis; afirst change unit, arranged between the Z base and the XY stage, thefirst change unit being configured to change the slant of the XY stagewith respect to the Z-axis direction based on a measurement result of afocus position of the second mark by the camera.
 6. The system accordingto claim 5, wherein the first change unit comprises a support mechanismplaced on a surface of the Z base vertical to the Z-axis direction andincluding a plurality of ΔZ lift pins configured to individually movethe XY stage in the Z-axis direction, and a driving mechanism configuredto drive the plurality of ΔZ lift pins in the Z-axis direction.
 7. Thesystem according to claim 6, wherein the first change unit supports theXY stage at three points by three ΔZ lift pins.
 8. The system accordingto claim 7, wherein of the three ΔZ lift pins, two ΔZ lift pins arearranged at positions parallel to the X-axis direction, and a remainingΔZ lift pin is arranged on a farther end side than the two ΔZ lift pinswith respect to a microscope base stand of the microscope body such thatthe three ΔZ lift pins form a triangle.
 9. The system according to claim6, wherein the first change unit comprises an elastic member configuredto bias and press the XY stage against the ΔZ lift pins.
 10. The systemaccording to claim 6, further comprising: a first obtaining unitconfigured to obtain a scale value corresponding to a moving amount ofthe Z base in the Z-axis direction; and a second obtaining unitconfigured to obtain, near each of the plurality of ΔZ lift pins, amoving amount of the XY stage in the Z-axis direction by the ΔZ liftpin.
 11. The system according to claim 10, wherein the first change unitcomprises a ΔZ base fixed to the Z base, and wherein the supportmechanism is fixed to the ΔZ base, and sensors that constitute the firstobtaining unit and the second obtaining unit are fixed to the ΔZ base.12. The system according to claim 10, wherein the XY stage furthercomprises a ΔΘ stage on which a slide is placed, the ΔΘ stagecomprising: (a) a rotary stage configured to pivot in a state in whichthe slide is placed; and (b) a second change unit configured to change aslant of an XY plane of the ΔΘ stage with respect to the XY plane of theXY stage.
 13. The system according to claim 12, wherein the secondchange unit comprises a plurality of dZ lift pins configured toindividually move in the Z-axis direction, the plurality of dZ lift pinssupporting the ΔΘ stage on the XY stage.
 14. The system according toclaim 13, wherein the second change unit supports the ΔΘ stage at threepoints by three dZ lift pins.
 15. The system according to claim 14,wherein of the three dZ lift pins, two dZ lift pins are arranged atpositions parallel to the X-axis direction, and a remaining dZ lift pinis arranged on a far end side with respect to the microscope base standsuch that the three dZ lift pins form a triangle.
 16. The systemaccording to claim 13, wherein the second change unit comprises anelastic member configured to bias and press the ΔΘ stage against the dZlift pins.
 17. The system according to claim 13, further comprising athird obtaining unit configured to obtain, near each of the plurality ofdZ lift pins, a moving amount of the ΔΘ stage in the Z-axis directionwith respect to the XY stage.
 18. The system according to claim 17,wherein a fixing unit configured to fix a moving mechanism configured tomove the plurality of dZ lift pins that support the ΔΘ stage is providedon the XY stage and, a sensor that constitutes the third obtaining unitis fixed to the XY stage.
 19. The system according to claim 17, whereineach of the first obtaining unit, the second obtaining unit, and thethird obtaining unit comprises a scale and a sensor configured to detectan initial position and a scale and a sensor configured to read a movingamount.
 20. The system according to claim 13, wherein the first changeunit comprises a ΔZ base fixed to the Z base, and wherein at initialpositions of the plurality of ΔZ lift pins, positions of distal ends ofthe plurality of ΔZ lift pins are located at the same distance from asurface of the ΔZ base.
 21. The system according to claim 20, wherein atthe initial positions of the plurality of ΔZ lift pins, a slideplacement surface of the ΔΘ stage becomes parallel to the XY plane ofthe XY stage.
 22. The system according to claim 10, wherein an initialposition of the first obtaining unit is a position at which a distal endof the objective lens and an observation surface of the XY stage do notcome into contact regardless of a position of each of the plurality ofΔZ lift pins and the plurality of dZ lift pins in a movable range.